diff --git a/src/A. Zero Sum.py b/src/A. Zero Sum.py
new file mode 100644
index 0000000..d2e1fab
--- /dev/null
+++ b/src/A. Zero Sum.py	
@@ -0,0 +1,41 @@
+# https://codeforces.com/contest/2247/problem/A
+
+def solve():
+  n = int(input())
+  a = list(map(int, input().split()))
+
+  S = sum(a)
+
+  if S == 0:
+    return print("YES")
+
+  if S % 2 != 0:
+    return print("NO")
+
+  if n <= abs(S):
+    return print("NO")
+
+  p = 0
+  s = 1 if S > 0 else -1
+  i = 0
+  while i < n - 1:
+    if a[i] == s and a[i + 1] == s:
+      p += 1
+      i += 2
+    else:
+      i += 1
+
+  if p * 2 < abs(S):
+    return print("NO")
+
+  return print("YES")
+
+  # solution :
+  # if sum(a) % 4 == 0:
+  #       print("YES")
+  #   else:
+  #       print("NO")
+
+t = int(input())
+for _ in range(t):
+    solve()
\ No newline at end of file
diff --git a/src/B. Yet Another Constructive.py b/src/B. Yet Another Constructive.py
new file mode 100644
index 0000000..eae993a
--- /dev/null
+++ b/src/B. Yet Another Constructive.py	
@@ -0,0 +1,16 @@
+# https://codeforces.com/contest/2247/problem/B
+
+# i gave up
+
+import math
+
+def solve():
+  n, k, m = map(int, input().split())
+
+  a = []
+
+  print(n, k, m)
+
+t = int(input())
+for _ in range(t):
+    solve()
\ No newline at end of file
diff --git a/src/C. Inversion of a Subsequence.py b/src/C. Inversion of a Subsequence.py
new file mode 100644
index 0000000..191385b
--- /dev/null
+++ b/src/C. Inversion of a Subsequence.py	
@@ -0,0 +1,27 @@
+# https://codeforces.com/contest/2247/problem/C
+
+# solved !!!!
+
+def solve():
+  n = int(input())
+  a = list(map(int, input().split()))
+  b = list(map(int, input().split()))
+
+  if a == b:
+    return print(0)
+
+  diff = [a[i] - b[i] for i in range(n)]
+
+  if all(not diff[i] or diff[i] == -1 for i in range(n)):
+    if 1 in a and 0 in b:
+      return print(2)
+    return print(-1)
+
+  if sum([a[i] if diff[i] else 0 for i in range(n)]) % 2 == 0:
+    return print(2)
+  else:
+    return print(1)
+
+t = int(input())
+for _ in range(t):
+    solve()
\ No newline at end of file