//8.5 二分圖最大匹配

#include<cstdio>
int e[101][101];
int match[101];
int book[101];
int n,m;
int dfs(int u)
{
    int i;
    for(i=0;i<=n;i++)
    {
        if(book[i]==0&&e[u][i]==1)
        {
            book[i]=1;
            if(match[i]==0||dfs(match[i]))
            {
                match[i]=u;
                match[u]=i;
                return
 
 1;
            }
        }
    }
    return 0;
}
int main()
{
    freopen("data.in","r",stdin);
    int i,j,t1,t2,sum=0;
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;i++)
    {
        scanf("%d%d",&t1,&t2);
        e[t1][t2]=1;
        e[t2][t1]=1;
    }
    for(i=1;i<=n;i++)
    {
        for
 
(j=1;j<=n;j++)
            book[j]=0;
        if(dfs(i))
            sum++;
    }
    printf("%d",sum);
    return 0;
}