Vertex Cover

frog has a graph with nn vertices v(1),v(2),…,v(n)v(1),v(2),…,v(n) and mm edges (v(a1),v(b1)),(v(a2),v(b2)),…,(v(am),v(bm))(v(a1),v(b1)),(v(a2),v(b2)),…,(v(am),v(bm)).

She would like to color some vertices so that each edge has at least one colored vertex.

Find the minimum number of colored vertices.

Input

The input consists of multiple tests. For each test:

The first line contains 22 integers n,mn,m (2≤n≤500,1≤m≤n(n−1)22≤n≤500,1≤m≤n(n−1)2). Each of the following mm lines contains 22 integers ai,biai,bi (1≤ai,bi≤n,ai≠bi,min{ai,bi}≤301≤ai,bi≤n,ai≠bi,min{ai,bi}≤30)

Output

For each test, write 11 integer which denotes the minimum number of colored vertices.

Sample Input

    3 2    1 2    1 3    6 5    1 2    1 3    1 4    2 5    2 6

Sample Output

    1    2

#include <cstdio>#include <vector>#include <cstring>using namespace std;vector<int>map[505];bool vis[505];int conn[505];bool dfs(int x){    for(int i=0; i<map[x].size(); i++)    {        int y=map[x][i];        //printf("y=%d ",y);        if(!vis[y])        {            vis[y]=true;            if(conn[y]==0||dfs(conn[y]))            {                conn[y]=x;                conn[x]=y;                return true;            }        }    }    return false;}int main(){    int n,m;    while(~scanf("%d %d",&n,&m))    {        memset(conn,0,sizeof(conn));        memset(map,0,sizeof(map));        for(int i=0; i<m; i++)        {            int a,b;            scanf("%d %d",&a,&b);            map[a].push_back(b);            map[b].push_back(a);        }        int ans=0;        for(int i=1; i<=n; i++)        {            if(!conn[i]){            memset(vis,false,sizeof(vis));            if(dfs(i))                ans++;            }        }        printf("%d\n",ans);    }    return 0;}