#include <fstream>
#include <vector>

#define NMAX 100005
using namespace std;
vector <int> lAdiac[NMAX];
bool viz[NMAX];

bool isFullyVisited (bool viz[], int n){
    for(int i = 1; i <= n; ++i){
        if(!viz[i]){
            return false;
        }
    }
    return true;
}

void DFS(int start){
    viz[start] = true;
    int sz = lAdiac[start].size();
    for(int i = 0; i < sz; ++i){
        if(!viz[lAdiac[start][i]]){
            DFS(lAdiac[start][i]);
        }
    }
}



int getCC(int n){
    DFS(1);
    int ct = 1;
    while(!isFullyVisited(viz, n)){
        for(int i = 1; i <= n; ++i){
            if(!viz[i]){
                DFS(i);
                ct++;
            }
        }
    }
    return ct;
}

int main()
{
    ifstream f("dfs.in");
    int n, m;
    f >> n >> m;
    while(m){
        int a, b;
        f >> a >> b;
        lAdiac[a].push_back(b);
        lAdiac[b].push_back(a);
        m --;
    }
    f.close();
    int cc = getCC(n);
    ofstream g("dfs.out");
    g << cc;
    g.close();
    return 0;
}