#include <fstream>

using namespace std;

ifstream f ("dfs.in");
ofstream g ("dfs.out");

int n, m;
int a[1005][1005];
bool used[1005];

void Read ()
{
   f >> n >> m;
    for (int i=1; i<=m; i++)
    {
        int x, y;
        f >> x >> y;
        a[x][y] = a[y][x] = 1;
    }
}

void Dfs (int nod)
{
   used[nod] = 1;
   for (int j=1; j<=n; j++)
   {
       if (a[nod][j] && !used[j])
          Dfs(j);
   }
}

void Solve ()
{
   int sol = 0;
    for (int i=1; i<=n; i++)
    {
        if (!used[i])
        {
            sol ++;
            Dfs(i);
        }
    }
   g << sol;
}

int main()
{
  Read();
  Solve();
    return 0;
}