#include <iostream>
#include <fstream>
#include <vector>
#include <deque>

using namespace std;

void vizitat( vector < vector < int > > &vecini, vector < int > &culoare, vector < int > &d, vector < int > &f, int &u, int &timp ){
    culoare[u] = 1;
    timp++;
    d[u] = timp;
    for( int i = 0; i < vecini[u].size(); i++ ){
        if( culoare[ vecini[u][i] ] == 0 ){
            vizitat(vecini,culoare,d,f,vecini[u][i],timp);
        }
    }
    culoare[u] = 2;
    timp++;
    f[u] = timp;
}

int main(){
    ifstream fin("dfs.in");
    ofstream fout("dfs.out");
    vector < vector < int > > vecini;
    int nr_noduri, nr_muchii;
    fin >> nr_noduri >> nr_muchii;
    for(int i = 0; i <= nr_noduri; i++){
        vector < int > v;
        vecini.push_back(v);
    }
    for( int i = 0; i < nr_muchii; i++ ){
        int intrare, iesire;
        fin >> intrare >> iesire;
        vecini[intrare].push_back(iesire);
        vecini[iesire].push_back(intrare);
    }
    vector < int > culoare, d, f;
    for( int i = 0; i <= nr_noduri; i++ ){
        culoare.push_back(0);
        d.push_back(-1);
        f.push_back(-1);
    }
    int timp = 0;
    int contor = 0;
    for( int i = 1; i <= nr_noduri; i++ ){
        if( culoare[i] == 0 ){
            contor++;
            vizitat(vecini, culoare, d, f, i,timp);
        }
    }
    fout << contor;
}