#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,m,viz[2000];
int a[1000][1000];
void citire()
{
    int i,x,y;
    fin>>n>>m;
    for (i=1;i<=n;i++)
    {
        fin>>x>>y;
        a[x][y]=a[y][x]=1;
    }
}
void dfs(int x)
{
    int i;
    viz[x]=1;
    for (i=1;i<=n;i++)
        if (a[x][i]==1&&viz[i]==0)
            viz[i]=viz[x]+1;
}
int main()
{
    citire();
    int nrc=0,i;
    for (i=1;i<=n;i++)
        if (viz[i]==0)
            {
                nrc++;
                dfs(i);
            }
    fout<<nrc<<'\n';
    return 0;
}