#include<vector>
#include<stack>
#include<fstream>
#include<algorithm>
using namespace std;

#define nn 100001
#define pb push_back
vector <int> g[nn];
int n,m,nrc,v[nn];

void citire(){
    int a,b;
    ifstream fin("dfs.in");
    fin>>n>>m;
    for(;m;--m){
        fin>>a>>b;
        g[a].pb(b);
        g[b].pb(a);
    }
}
void afisare(){
    FILE *f=fopen("dfs.out","w");
    fprintf(f,"%d",nrc);
}
void dfs(int arg){//atetie ca e recursiv
    int coada[nn],st,dr,i;
    st=dr=1;
    coada[1]=arg;
    v[arg]=1;
    while(st<=dr){
        int k=coada[st++];
            for(i=0;i<g[k].size();++i){
                int kk=g[k][i];
                if(!v[kk]){
                    coada[++dr]=kk;
                    v[kk]=1;
                }
            }
    }
}
int main(){
    citire();
    for(int i=1;i<=n;++i)
        if(!v[i]){
            dfs(i);
            ++nrc;
        }
    afisare();
    return 0;
}