#include<fstream>
#include<vector>
#include<cstring>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int n,m,x,y,i,j,det[100005],con,fin;
vector<int>v[100005];
bool viz[100005];
void dfs(int nod)
{
    viz[nod]=1;
    for(int i=0;i<v[nod].size();i++)
      if(viz[v[nod][i]]==0)
        dfs(v[nod][i]);
}
int main()
{
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
    {
        memset(viz,0,sizeof(viz));
        viz[i]=1;
        con=0;
        for(j=0;j<v[i].size();j++)
          if(viz[v[i][j]]==0)
          {
              con++;
              dfs(v[i][j]);
          }
        det[i]=con;
    }
    bool ok=0;
    for(i=1;i<=n;i++)
      if(det[i]>1)
        if(ok==0)
        {
            fin+=det[i];
            ok=1;
        }
        else
          fin+=det[i]-1;
    g<<fin;
    return 0;
}