#include <iostream>
#include <fstream>

#define max 10005
using namespace std;
int a[max][max];
int viz[max];
int n,m;
void citire()
{
    scanf("%d %d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        int x,y;
        scanf("%d %d",&x,&y);
        if(x!=y)
            a[x][y]=a[y][x]=1;
    }
}
void dfs(int x)
{
    viz[x]=1;
    for(int i=1;i<=n;i++)
        if(viz[i]==0 && a[x][i]==1)
            dfs(i);
}
int main()
{
    freopen("dfs.in","r",stdin);
    ofstream f("dfs.out");
    citire();
    int k=0;
    for(int i=1;i<=n;i++)
        if(viz[i]==0)
            k++,dfs(i);
    f<<k;
    return 0;
}