1 #include<bits/stdc++.h> 2 #define LL long long 3 #define fi first 4 #define se second 5 #define mk make_pair 6 #define pii pair<int,int> 7 8 using namespace std; 9 10 const int N=2000+7; 11 const int M=1e4+7; 12 const int inf=0x3f3f3f3f; 13 const LL INF=0x3f3f3f3f3f3f3f3f; 14 const int mod=1e9 + 7; 15 16 int n, m, vis[N], match[N]; 17 bool edge[N][N]; 18 19 int path(int u) { 20 for(int v = 1; v <= n; v++) { 21 if(edge[u][v] && !vis[v]) { 22 vis[v] = 1; 23 if(match[v] == -1 || path(match[v])) { 24 match[v] = u; 25 return 1; 26 } 27 } 28 } 29 return 0; 30 } 31 32 int main() { 33 memset(match, -1, sizeof(match)); 34 scanf("%d%d", &n, &m); 35 for(int i = 1; i <= m; i++) { 36 int x, y; scanf("%d%d", &x, &y); 37 x++, y++; 38 edge[i][x] = edge[i][y] = 1; 39 } 40 int ans = 0; 41 for(int i = 1; i <= m; i++) { 42 memset(vis, 0, sizeof(vis)); 43 if(path(i)) ans++; 44 else break; 45 } 46 printf("%d ", ans); 47 return 0; 48 }