#include <iostream>
#include <fstream>
using namespace std;
int c[100001],n,m,a[1001][1001],p,u,v[1001],con;
ifstream fin ("dfs.in");
ofstream fout ("dfs.out");
void adancime (int k)
{
    int i;
    u++;
    c[u]=k;
    v[k]=1;
    for (i=1;i<=n;i++)
        if (a[k][i]==1&&v[i]==0)
        adancime(i);
}
int main()
{
    int i,j,h;
    fin>>n>>m;
    for (h=1;h<=m;h++)
    {
        fin>>i>>j;
        a[i][j]=1;
        a[j][i]=1;
    }
    for (i=1;i<=n;i++)
    {
        if (v[i]==0)
        {
            adancime(i);
            con++;
        }
    }
    fout<<con;
    fin.close();
    fout.close();
    return 0;
}