#include<fstream>
using namespace std;
int n,m,t[100002],nrc;
int rad(int x)
{
    while(t[x])
        x=t[x];
    return x;
}

void reuniune(int x,int y)
{
    if(rad(x)!=rad(y))
    {
        t[x]=rad(y);
        nrc--;
    }
}
int main()
{
    ifstream fin("dfs.in");
    fin>>n>>m;
    nrc=n;
    for( ; m ;m--)
    {
        int i,j;
        fin>>i>>j;
        reuniune(i,j);
    }
    ofstream fout("dfs.out");
    fout<<nrc;
    return 0;

}