diff --git a/baekjoon/1253.py b/baekjoon/1253.py
new file mode 100644
index 0000000..1499a27
--- /dev/null
+++ b/baekjoon/1253.py
@@ -0,0 +1,23 @@
+N = int(input())
+A = list(map(int, input().split()))
+A.sort()
+
+res = 0
+for i in range(N):
+  target = A[i]
+  start, end = 0, len(A)-1
+  while start < end:
+    if A[start] + A[end] == target:
+      if start == i:
+        start += 1
+      elif end == i:
+        end -= 1
+      else:
+        res += 1
+        break
+    elif A[start] + A[end] > target:
+      end -= 1
+    elif A[start] + A[end] < target:
+      start += 1
+
+print(res)
\ No newline at end of file
diff --git a/baekjoon/1520.py b/baekjoon/1520.py
new file mode 100644
index 0000000..78c9b74
--- /dev/null
+++ b/baekjoon/1520.py
@@ -0,0 +1,25 @@
+import sys
+sys.setrecursionlimit(10 ** 8)
+input = sys.stdin.readline
+
+M, N = map(int, input().split())
+graph = []
+for _ in range(M):
+  graph.append(list(map(int, input().split())))
+dp = [[-1]*N for _ in range(M)]
+dx = [0, 1, 0, -1]
+dy = [1, 0 , -1, 0]
+
+def sol(x, y):
+  if x==M-1 and y == N-1:
+    return 1
+  if dp[x][y] == -1:
+    dp[x][y] = 0  # 방문 처리
+    for i in range(4):
+      nx, ny = x+dx[i], y+dy[i]
+      if 0<=nx<M and 0<=ny<N and graph[nx][ny] < graph[x][y]:
+        dp[x][y] += sol(nx, ny)
+
+  return dp[x][y]
+
+print(sol(0, 0))
\ No newline at end of file
diff --git a/baekjoon/2133.py b/baekjoon/2133.py
new file mode 100644
index 0000000..27afdbf
--- /dev/null
+++ b/baekjoon/2133.py
@@ -0,0 +1,8 @@
+N = int(input())
+dp = [0] * 31
+dp[2] = 3
+for i in range(4, N+1):
+  if i%2 == 0:
+    dp[i] = dp[i-2]*3 + sum(dp[:i-2])*2 + 2
+
+print(dp[N])
\ No newline at end of file
diff --git a/baekjoon/2293.py b/baekjoon/2293.py
new file mode 100644
index 0000000..6e9de4d
--- /dev/null
+++ b/baekjoon/2293.py
@@ -0,0 +1,18 @@
+# 동전을 하나씩 넣으며 dp[i]의 경우 i를 만드는 경우의 수 계산
+# 예시 : i=4이고, 동전 2 넣을 때
+# dp[4] = dp[4] + dp[4-2]
+# 1로 4 만드는 경우 (dp[4]) + 2 만든 거에 2 넣는 경우의 수 (dp[4-2])
+
+n, k = map(int, input().split())
+coins = []
+for _ in range(n):
+  coins.append(int(input()))
+
+dp = [0] * (k+1)
+dp[0] = 1
+
+for coin in coins:
+  for i in range(coin, k+1):
+    dp[i] += dp[i-coin]
+
+print(dp[-1])
\ No newline at end of file
diff --git a/baekjoon/29751.py b/baekjoon/29751.py
new file mode 100644
index 0000000..4871dd5
--- /dev/null
+++ b/baekjoon/29751.py
@@ -0,0 +1,3 @@
+W, H = map(int, input().split())
+
+print(f"{W*H/2:.1f}")
\ No newline at end of file