提交时间:2026-06-17 06:49:46

运行 ID: 91824

import sys def main(): input = sys.stdin.read().split() ptr = 0 N = int(input[ptr]) ptr += 1 M = int(input[ptr]) ptr += 1 deg = [0] * (N + 1) edges = [] for _ in range(M): u = int(input[ptr]) ptr += 1 v = int(input[ptr]) ptr += 1 edges.append((u, v)) deg[u] += 1 deg[v] += 1 ans = 0 for u, v in edges: ans += deg[u] * deg[v] print(ans) if __name__ == '__main__': main()