#include <fstream>
 using namespace std;
 ifstream fin ("dfs.in");
 ofstream fout ("dfs.out");
int a[1005][1005], n, m, viz[1005], cnt;

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

void DFS(int nod)
{
    int i;
    viz[nod] = 1;
    for (i = 1; i <= n; i++) if (!viz[i] && a[nod][i]) DFS(i);
}

int main()
{
    citire();
    int i;
    for (i = 1; i <= n; i++) if (!viz[i]) { cnt++; DFS(i);}
    fout<<cnt;
    return 0;
}