#include <fstream>
#include <vector>
using namespace std;
int const Lmax = 100001;
vector<int> v[Lmax];
bool viz[Lmax];
int n, m;

void dfs(int node){
    viz[node] = true;
    for(int j : v[node])
        viz[j]=true;
}

int main()
{
    ifstream fin("dfs.in");
    ofstream fout("dfs.out");
    fin>>n>>m;
    while(m--){
        int x, y;
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    int cnt = 0;
    for(int i=1;i<=n;i++){
        if(!viz[i]){
            cnt++;
            dfs(i);
        }
    }
    fout<<cnt;
    return 0;
}