#include <fstream>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
struct nod{
    int inf;
    nod *urm;
};
nod *l[200001];
int n,m;
bool v[100001];
void cit(){
    int i,j,k;
    nod *q;
    fin>>n>>m;
    for(i=1;i<=n;i++)
        l[i]=0;
    for(k=1;k<=m;k++){
        fin>>i>>j;
        q=new nod;
        q->inf=j;
        q->urm=l[i];
        l[i]=q;
        q=new nod;
        q->inf=i;
        q->urm=l[j];
        l[j]=q;
    }
    fin.close();
}
void dfs(int k){
    nod *q;
    int i;
    v[k]=1;
    q=l[k];
    while(q!=0){
        i=q->inf;
        if(v[i]==0)
            dfs(i);
        q=q->urm;
    }
}
int main(){
    cit();
    int i,nr=0;
    for(i=1;i<=n;i++)
        if(v[i]==0){
            nr++;
            dfs(i);
        }
    fout<<nr;
    fout.close();
    return 0;
}