#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 1e5 + 5;
vector <int> g[NMAX];
int comp[NMAX];

void bfs(int start){
    queue <int> cod;

    cod.push(start);

    while(!cod.empty()){
        int ax = cod.front();
        cod.pop();

        comp[ax] = start;
        for(auto &it: g[ax])
            if(comp[it] == 0)
                cod.push(it);
    }
}

int main()
{
    int n, m, i, j;

    fin >> n >> m;
    for(i = 1; i <= m; ++i){
        int a, b;
        fin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }

    int ans = 0;

    for(i = 1; i <= n; ++i)
        if(comp[i] == 0){
            ++ans;
            bfs(i);
        }

    fout << ans;

    return 0;
}