#include <iostream>
#include <vector>
#include <queue>
#include <fstream>

using namespace std;

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

class Graf{
    private:
        int n,cc;
        vector<vector<int>> muchii;
        vector<int> viz;
    public:
        int getN();
        void addMuchie(int x, int y);
        void dfs(int x);
        void dfs_init();
        Graf();
        Graf(int n);
};
Graf::Graf(int n){
    cc = 0;
    this->n = n;
    vector<int> temp;
    for(int i=0;i<=n;i++){
        muchii.push_back(temp);
        viz.push_back(0);
    }
}

int Graf::getN (){
    return n;
}
void Graf::addMuchie(int x, int y){
    muchii[x].push_back(y);
}

void Graf::dfs(int x){
    viz[x]=1;
    for(auto i: muchii[x]){
        if(!viz[i])dfs(i);
    }
}
void Graf::dfs_init(){
    for(int i=1;i<=n;i++){
        if(!viz[i]){
            dfs(i);
            cc++;
        }
    }
    out << cc;
}

int main(){
    int n,m,s;
    in >> n >> m;
    Graf graf1(n);
    int x, y;
    for(int i=1;i<=m;i++){
        in >> x >> y;
        graf1.addMuchie(x,y);//adauga muchii
        graf1.addMuchie(y,x);
    }
    graf1.dfs_init();
    return 0;
}