#include <fstream>
#include <vector>
#include <bitset>
using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

int n,i,a,b,ccon=0,m;
vector<int> A[100001];
bitset <100001> vi;

void dfs(int nod) {
    vector<int>::iterator it;
    int x;vi[nod]=1;
    for (it=A[nod].begin();it!=A[nod].end();it++) {
        x=*it;
        if (vi[x]==0) dfs(x);
    }
    return;
}

int main () {
    f >> n >> m;
    for (i=1;i<=m;i++) {
        f >> a >> b;
        A[a].push_back(b);
        A[b].push_back(a);
    }
    for (i=1;i<=n;i++) if (vi[i]==0) {ccon++;dfs(i);}
    g << ccon << '\n';
    f.close();g.close();
    return 0;
}