#include <bits/stdc++.h>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int cnt;
bool pz[100001];
unordered_map<int,list <int>> matr;

void DFS(int nr)
{
    for(int i : matr[nr])
    if(pz[i]==0)
    {
        pz[i]=1;
        DFS(i);
    }
}
int main()
{
    int N,M;
    fin>>N>>M;
    while(M)
    {
        int x,y;
        fin>>x>>y;
        matr[x].push_back(y);
        matr[y].push_back(x);
        M--;
    }

    for(int c=0;c<N;c++)
    {
        if(pz[c+1]==0)
        {
            cnt++;
            pz[c+1]=1;
            DFS(c+1);
        }
    }
    fout<<cnt;
    return 0;
}