#include <iostream>
#include <fstream>

using namespace std;

ifstream in("dfs.in");
ofstream out("dfs.out");

const int NMAX=100001;
const int MMAX=200001;
int lst[NMAX], vf[2*MMAX], urm[2*MMAX];
bool viz[NMAX];
int n, m, nr;

void adauga(int x, int y)
{
    ++nr;
    vf[nr]=y;
    urm[nr]=lst[x];
    lst[x]=nr;
}

void dfs(int x)
{
    viz[x]=true;
    for(int p=lst[x];p;p=urm[p])
        if(!viz[vf[p]]) dfs(vf[p]);
}

int main()
{
    in >> n >> m;
    int x, y;
    while(in >> x >> y)
    {
        adauga(x, y);
        adauga(y, x);
    }
    int nr=0;
    for(int i=1; i<=n; i++)
        if(!viz[i])
        {
           nr++;
           dfs(i);
        }

    out << nr;
    return 0;
}