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

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

int n, m, nc;
bitset <100001> viz;
vector <int> A[100001];
list <int> C;

void cit(){
    int x, y;
    f>>n>>m;
    for (int i=1;i<=n;++i)
        A[i].push_back(0);
    for (int i=1;i<=m;++i){
        f>>x>>y;
        A[x][0]++;
        A[y][0]++;
        A[x].push_back(y);
        A[y].push_back(x);
    }
}

void bfs(int x){
    int prim, ultim;
    viz[x]=1;
    C.push_back(x);
    while(!C.empty()){
        int y=C.front();
        C.pop_front();
        for (int i=1;i<=A[y][0];++i){
            if (!viz[A[y][i]]){
                viz[A[y][i]]=1;
                C.push_back(A[y][i]);
            }
        }
    }
}

void dfs(int x){
    viz[x]=1;
    for (int i=1; i<=A[x][0]; ++i){
        if (!viz[A[x][i]]) dfs(A[x][i]);
    }
}

int main(){
    cit();
    for (int i=1;i<=n;++i)
        if (!viz[i]){
            nc++;
            //dfs(i);
            bfs(i);
        }
    g<<nc<<'\n';
    g.close();
    return 0;
}