//用并查集将块缩成点
#include < iostream >
#include < vector >
using   namespace  std;
vector < int > list[ 5001 ];   
 int  low[ 5001 ];
 int  d[ 5001 ],dep[ 5001 ];
 int  color[ 5001 ];
 int  n,m;
 int  bridge[ 10001 ][ 2 ];
 int  p[ 5001 ],rank[ 5001 ],cnt,tol,num = 0 ;
 int  ncon,belong[ 5001 ];
 void  Init()
{
     int  i;
     for (i = 1 ;i <= n;i ++ )
    {
        p[i] = i;
        rank[i] = 0 ;
    }
}
 int  Find( int  x)
{
     if (x != p[x])
        p[x] = Find(p[x]);
     return  p[x];
}
 int  Union( int  x, int  y)
{
     int  a = Find(x);
     int  b = Find(y);
     if (rank[a] > rank[b])
    {
        p[b] = a;
    }
     else
    {
        p[a] = b;
         if (rank[a] == rank[b])
        {
            rank[b] ++ ;
        }
    }
     return   0 ;
}
 int  DFS( int  u, int  fa, int  t)
{
    color[u] = 1 ;
    dep[u] = low[u] = t;
    tol = 0 ;
     int  tofa = 0 ;
     int  i,v;
     for (i = 0 ;i < list[u].size();i ++ )
    {
        v = list[u][i];
         if (color[v] == 0 )
        {
            DFS(v,u,t + 1 );
            tol ++ ;
            low[u] = min(low[u],low[v]);
             if (low[v] <= dep[u])
                Union(u,v);
             if (low[v] > dep[u])
            {
                bridge[num][ 0 ] = u;
                bridge[num ++ ][ 1 ] = v;
            }
        }
         else   if (v != fa || tofa)
        {
            low[u] = min(low[u],dep[v]);
        }
         if (v == fa) tofa = 1 ; 

    }
     return   0 ;
}
 int  DC()
{
     int  i;
     for (i = 1 ;i <= n;i ++ )
    {
        belong[i] =- 1 ;
    }
     for (i = 1 ;i <= n;i ++ )
    {
         int  k = Find(i);
         if (belong[k] ==- 1 )
            belong[k] =++ ncon;
        belong[i] = belong[k];
    }
     for (i = 0 ;i < num;i ++ )
    {
        d[belong[bridge[i][ 0 ]]] ++ ;
        d[belong[bridge[i][ 1 ]]] ++ ;
    }
     for (i = 1 ;i <= ncon;i ++ )
    {
         if (d[i] == 1 )
            cnt ++ ;
    }
     return  (cnt + 1 ) / 2 ;

}
 int  main()
{
     while (scanf( " %d%d " , & n, & m) != EOF)
    {
        cnt = 0 ;
        num = 0 ;
        memset(list, 0 , sizeof (list));
        memset(d, 0 , sizeof (d));
        memset(dep, 0 , sizeof (dep));
        memset(low, 0 , sizeof (low));
        memset(color, 0 , sizeof (color));
         int  a,b;
         while (m -- )
        {
            scanf( " %d%d " , & a, & b);
            list[a].push_back(b);
            list[b].push_back(a);
        }
        Init();
         int  i;
         for (i = 1 ;i <= n;i ++ )
        {
             if ( ! color[i])
                DFS(i, - 1 , 1 );
        }
        printf( " %d\n " ,DC());
    }
    system( " pause " );
     return   0 ;
}