#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>using namespace std;#define maxn 5005#define maxm 10005struct Edge{ int v, next;} edge[maxm];int n, m;int head[maxn];bool hash[maxn][maxn];int ecount, tcount;int dfn[maxn], vis[maxn], low[maxn], degree[maxn];void addedge(int a, int b){ edge[ecount].v = b; edge[ecount].next = head[a]; head[a] = ecount; hash[a][b] = hash[b][a] =true; ecount++;}void input(){ memset(head, -1, sizeof(head)); ecount =0; scanf("%d%d", &n, &m); for (int i =0; i < m; i++) { int a, b; scanf("%d%d", &a, &b); a--; b--; if (hash[a][b]) continue; addedge(a, b); addedge(b, a); }}void dfs(int fa, int u){ vis[u] =true; low[u] = dfn[u] = tcount++; for (int i = head[u]; i !=-1; i = edge[i].next) { int v = edge[i].v; if (v == fa) continue; if (!vis[v]) dfs(u, v); low[u] = min(low[u], low[v]); }}int tarjan(){ memset(dfn, 0, sizeof(dfn)); memset(vis, 0, sizeof(vis)); memset(degree, 0, sizeof(degree)); tcount =0; dfs(0, 0); int ret =0; for (int i =0; i < n; i++) for (int j = head[i]; j !=-1; j = edge[j].next) { int v = edge[j].v; if (low[i] != low[v]) degree[low[i]]++; } for (int i =0; i < n; i++) if (degree[i] ==1) ret++; return (ret +1) /2;}int main(){ input(); int ans = tarjan(); printf("%dn", ans); return 0;}
