#include <bits/stdc++.h>
#define NMAX 100000
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
vector<int>v[NMAX];
bool viz[NMAX];
int q[NMAX], inceput, sfarsit, n, m, i, nr;
void bfs(int x);
int main()
{
    int x, y;
    fin>>n>>m;
    for (i=1; i<=m; i++) {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (i=1; i<=n; i++) {
        if (viz[i]==0) {
            bfs(i);
            nr++;
        }
    }
    fout<<nr;
    return 0;
}
void bfs(int x) {
    sfarsit++;
    q[inceput]=x;
    while (inceput<=sfarsit) {
        //fout<<q[inceput]<<' ';
        viz[q[inceput]]=1;
        inceput++;
        for (auto y:v[x]) {
            if (viz[y]==0) q[++sfarsit]=y;
        }
    }
}