#include <bits/stdc++.h>

using namespace std;

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

const int maxDim = 1e5 + 5;

vector <int> adList[maxDim];
bool viz[maxDim];
int N , M , ans;

void DFS (int n)
{
    viz[n] = 1;
    for(int i = 0 ; i < adList[n].size() ; ++i)
        if(viz[adList[n][i]] == 0)
            DFS(adList[n][i]);
}

int main()
{
    fin >> N >> M;
    for(int i = 1 ; i <= M ; ++i)
    {
        int x , y;
        fin >> x >> y;
        adList[x].push_back(y);
        adList[y].push_back(x);
    }
    for(int i = 1 ; i <= N ; ++i)
        if(viz[i] == 0)
        {
            DFS(i);
            ++ans;
        }
    fout << ans;
}