#include <bits/stdc++.h>

using namespace std;

const int MAXN = 200004;

int cnt = 0;

vector< int > gr[MAXN];
vector< int > conexa[MAXN];
bool viz[MAXN];
void dfs(int node)
{
    viz[node]=1;

    conexa[cnt].push_back(node);

    for(auto &x : gr[node]){
        if(!viz[x]){
            dfs(x);
        }
    }
}

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

    int n, m;
    fin>>n>>m;

    for(int i = 1; i <= m; i++){
        int x,y;
        fin >> x >> y;
        gr[x].push_back(y);
        gr[y].push_back(x);
    }
    for(int i = 1; i <= n; i++){
        if(!viz[i]){
            cnt+=1;
            dfs(i);
        }
    }
    fout << cnt;
    return 0;
}