diff --git "a/Limchaeyoung/[BOJ] \354\210\230 \353\254\266\352\270\260.py" "b/Limchaeyoung/[BOJ] \354\210\230 \353\254\266\352\270\260.py"
new file mode 100644
index 0000000..533c95e
--- /dev/null
+++ "b/Limchaeyoung/[BOJ] \354\210\230 \353\254\266\352\270\260.py"	
@@ -0,0 +1,38 @@
+# https://www.acmicpc.net/problem/1744
+n = int(input())
+data = [int(input()) for i in range(n)]
+data.sort(reverse=True)
+idx, sum, num = len(data), 0, 0
+
+for i, d in enumerate(data):
+    if d < 1:
+        idx = i
+        break
+
+data1, data2 = data[:idx], data[idx:]
+data2.reverse()
+
+if data1:
+    for i, d in enumerate(data1):
+        if d == 1:
+            sum += 1
+            continue
+        if i % 2 == 0:
+            num = d
+        else:
+            num *= d
+            sum += num
+            num = 0
+    if num != 0: sum += num
+if data2:
+    for i, d in enumerate(data2):
+        if i % 2 == 0:
+            num = d
+        else:
+            num *= d
+            sum += num
+            num = 0
+    if num != 0: sum += num
+
+print(sum)
+
diff --git "a/Limchaeyoung/[BOJ] \354\210\250\353\260\224\352\274\255\354\247\210 3.py" "b/Limchaeyoung/[BOJ] \354\210\250\353\260\224\352\274\255\354\247\210 3.py"
new file mode 100644
index 0000000..f750433
--- /dev/null
+++ "b/Limchaeyoung/[BOJ] \354\210\250\353\260\224\352\274\255\354\247\210 3.py"	
@@ -0,0 +1,30 @@
+# https://www.acmicpc.net/status?user_id=hea_c&problem_id=13549&from_mine=1
+from collections import deque
+
+n, k = map(int, input().split())
+sec = [-1] * 100001
+s = [2, -1, 1]
+
+def bfs(n):
+    queue = deque([n])
+    sec[n] = 0
+    while queue:
+        q = queue.popleft()
+        for i in s:
+            if i == 2:
+                tp = 1
+                x = q * 2
+            else:
+                tp = 0
+                x = q + i
+            if 0 <= x <= 100000 and sec[x] == -1:
+                if tp:
+                    queue.append(x)
+                    sec[x] = sec[q]
+                else:
+                    queue.append(x)
+                    sec[x] = sec[q]+1
+            if x == k:
+                 return sec[x]
+
+print(bfs(n))
\ No newline at end of file
diff --git "a/Limchaeyoung/[BOJ] \354\210\250\353\260\224\352\274\255\354\247\210.py" "b/Limchaeyoung/[BOJ] \354\210\250\353\260\224\352\274\255\354\247\210.py"
new file mode 100644
index 0000000..af71228
--- /dev/null
+++ "b/Limchaeyoung/[BOJ] \354\210\250\353\260\224\352\274\255\354\247\210.py"	
@@ -0,0 +1,21 @@
+# https://www.acmicpc.net/problem/1697
+from collections import deque
+
+n, k = map(int, input().split())
+sec = [-1] * 100001
+s = [-1,1,2]
+
+def bfs(n):
+    queue = deque([n])
+    sec[n] = 0
+    while queue:
+        q = queue.popleft()
+        for i in s:
+            x = q * 2 if i == 2 else q + i
+            if 0 <= x <= 100000 and sec[x] == -1:
+                queue.append(x)
+                sec[x] = sec[q] + 1
+            if x == k:
+                 return sec[x]
+
+print(bfs(n))
\ No newline at end of file
diff --git "a/Limchaeyoung/[BOJ] \354\236\203\354\226\264\353\262\204\353\246\260 \352\264\204\355\230\270.py" "b/Limchaeyoung/[BOJ] \354\236\203\354\226\264\353\262\204\353\246\260 \352\264\204\355\230\270.py"
new file mode 100644
index 0000000..94736f9
--- /dev/null
+++ "b/Limchaeyoung/[BOJ] \354\236\203\354\226\264\353\262\204\353\246\260 \352\264\204\355\230\270.py"	
@@ -0,0 +1,11 @@
+# https://www.acmicpc.net/problem/1541
+st = input().split('-')
+num = []
+for s in st:
+    n = 0
+    ii = s.split('+')
+    for i in ii:
+        n += int(i)
+    num.append(n)
+answer = num[0] * 2 - sum(num)
+print(answer)
\ No newline at end of file
diff --git "a/Limchaeyoung/[PGS] \353\204\244\355\212\270\354\233\214\355\201\254.py" "b/Limchaeyoung/[PGS] \353\204\244\355\212\270\354\233\214\355\201\254.py"
new file mode 100644
index 0000000..60b0baf
--- /dev/null
+++ "b/Limchaeyoung/[PGS] \353\204\244\355\212\270\354\233\214\355\201\254.py"	
@@ -0,0 +1,15 @@
+# https://school.programmers.co.kr/learn/courses/30/lessons/43162#
+def dfs(graph, visited, v):
+    visited[v] = True
+    for i in range(len(graph[v])):
+        if not visited[i] and graph[v][i]:
+            dfs(graph, visited, i)
+
+def solution(n, computers):
+    cnt = 0
+    visited = [False] * n
+    for i in range(n):
+        if not visited[i]:
+            cnt += 1
+            dfs(computers, visited, i)
+    return cnt
\ No newline at end of file
diff --git "a/Limchaeyoung/[PGS] \353\213\250\354\206\215\354\271\264\353\251\224\353\235\274.py" "b/Limchaeyoung/[PGS] \353\213\250\354\206\215\354\271\264\353\251\224\353\235\274.py"
new file mode 100644
index 0000000..f2555f8
--- /dev/null
+++ "b/Limchaeyoung/[PGS] \353\213\250\354\206\215\354\271\264\353\251\224\353\235\274.py"	
@@ -0,0 +1,13 @@
+# https://school.programmers.co.kr/learn/courses/30/lessons/42884
+def solution(routes):
+    routes = sorted(routes, key=lambda x: (x[1], x[0]))
+    k = routes[0][1]
+    print(routes)
+    cnt = 1
+    for i in range(1, len(routes)):
+        if routes[i][0] <= k <= routes[i][0]:
+            continue
+        else:
+            cnt += 1
+            k = routes[i][1]
+    return cnt
\ No newline at end of file
diff --git "a/Limchaeyoung/[PGS] \353\262\240\354\212\244\355\212\270 \354\225\250\353\262\224.py" "b/Limchaeyoung/[PGS] \353\262\240\354\212\244\355\212\270 \354\225\250\353\262\224.py"
new file mode 100644
index 0000000..3b67fe7
--- /dev/null
+++ "b/Limchaeyoung/[PGS] \353\262\240\354\212\244\355\212\270 \354\225\250\353\262\224.py"	
@@ -0,0 +1,22 @@
+# https://school.programmers.co.kr/learn/courses/30/lessons/42579
+def solution(genres, plays):
+    data = {}
+    cnt = {}
+    answer = []
+    for i in range(len(genres)):
+        if genres[i] in data:
+            d = data[genres[i]]
+            d.append((i, plays[i]))
+            data[genres[i]] = d
+            cnt[genres[i]] += plays[i]
+        else:
+            data[genres[i]] = [(i, plays[i])]
+            cnt[genres[i]] = plays[i]
+    for i in data:
+        data[i] = sorted(data[i], key=lambda x: (-x[1], x[0]))
+    cnt = dict(sorted(cnt.items(), key=lambda x: -x[1]))
+    for c in cnt:
+        answer.append(data[c][0][0])
+        if len(data[c]) > 1:
+            answer.append(data[c][1][0])
+    return answer
\ No newline at end of file
diff --git "a/Limchaeyoung/[PGS] \354\240\204\355\231\224\353\262\210\355\230\270 \353\252\251\353\241\235.py" "b/Limchaeyoung/[PGS] \354\240\204\355\231\224\353\262\210\355\230\270 \353\252\251\353\241\235.py"
new file mode 100644
index 0000000..4d526ab
--- /dev/null
+++ "b/Limchaeyoung/[PGS] \354\240\204\355\231\224\353\262\210\355\230\270 \353\252\251\353\241\235.py"	
@@ -0,0 +1,10 @@
+# https://school.programmers.co.kr/learn/courses/30/lessons/42577
+def solution(phone_book):
+    pre = dict()
+    for p in phone_book:
+        for i in range(1, len(p)):
+            pre[p[:i]] = 1
+    for p in phone_book:
+        if p in pre:
+            return False
+    return True
\ No newline at end of file
diff --git "a/Limchaeyoung/[PGS] \354\271\264\355\216\253.py" "b/Limchaeyoung/[PGS] \354\271\264\355\216\253.py"
new file mode 100644
index 0000000..c3992b5
--- /dev/null
+++ "b/Limchaeyoung/[PGS] \354\271\264\355\216\253.py"	
@@ -0,0 +1,11 @@
+# https://school.programmers.co.kr/learn/courses/30/lessons/42842
+def solution(brown, yellow):
+    s = 0
+    for i in range(1, int(yellow**0.5)+1):
+        if yellow % i == 0:
+            y = yellow // i
+            b = (y + 2) * (i + 2) - yellow
+            if b == brown:
+                s = y
+                break
+    return [s+2, yellow//s+2]
\ No newline at end of file