#include <fstream>
#include <vector>
#define NMAX 100001

using namespace std;

vector<int> la[NMAX];
bool viz[NMAX];
int n, m;

void df(int x) {
    viz[x] = true;
    for(int i = 0; i < la[x].size(); i++) {
        if(!viz[la[x][i]])df(la[x][i]);
    }
}

int main() {
    ifstream fin("dfs.in");
    ofstream fout("dfs.out");
    fin >> n >> m;
    for(int i = 1; i <= m; i++) {
        int a, b;
        fin >> a >> b;
        la[a].push_back(b);
        la[b].push_back(a);
    }
    int s = 0;
    for(int i = 1; i <= n; i++) {
        if(!viz[i]){
            s++;
            df(i);
            int b = -1;
            for(int j = 1; j <= n; j++) {
                if(viz[j] == 0) {
                    b = j;
                    break;
                }
            }
            if(b != -1) {
                //cout << endl;
            }
        }
    }
    fout << s << endl;
    fin.close();
    fout.close();
    return 0;
}