#include <fstream>
#include <vector>
#define NMAX 100004

using namespace std;
ifstream fin ("dfs.in");
ofstream fout ("dfs.out");

vector <int> v[NMAX];
bool uz[NMAX];
int nr, n, m, i, x, y;

void rec (int vf);
int main()
{
 fin>>n>>m;
 for (i=1; i<=m; i++)
     {
      fin>>x>>y;
      v[x].push_back(y);
      v[y].push_back(x);
     }
 for (i=1; i<=n; i++)
     if (!uz[i])
        {
         nr++;
         rec(i);
        }
 fout<<nr<<'\n';
 return 0;
}

void rec (int vf)
{
 uz[vf]=1;
 while (!v[vf].empty())
       {
        if (!uz[v[vf].back()])
           rec(v[vf].back());
        v[vf].pop_back();
       }
}