#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int N,M;

vector <int> A[100005];

bool VIZ[100005];

void df(int N)
{
    if (VIZ[N]==0)
    {
        VIZ[N]=1;
        vector<int> :: iterator it;
        for (it=A[N].begin();it!=A[N].end();++it)
        {
            int v=(*it);
            if (VIZ[v]==0)
            {
                df(v);
            }
        }
    }
}

int main()
{
    fin >> N >> M;
    int i,a,b;
    for (i=1;i<=M;++i)
    {
        fin >> a >> b;
        A[a].push_back(b);
        A[b].push_back(a);
    }
    int rez=0;
    for (i=1;i<=N;++i)
    {
        if (VIZ[i]==0)
        {
            df(i);
            ++rez;
        }
    }
    fout << rez;
    return 0;
}