#include<cstdio>
#include<fstream>
#include<bitset>
#include<vector>
using namespace std;
vector<int>v[100000];
bitset<100000>viz;
vector<int>:: iterator it;
int n,m,s,cont,c[100000];
void citire(){
    ifstream f("dfs.in");
    f>>n>>m;
    for(int x,y,i=1;i<=m;++i){
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}
void dfs(int x){
    int k=1;
    c[k]=x;
    viz[x]=1;
    s++;
    while(k>0){
        int t=0;
            for(it=v[c[k]].begin(); it<v[c[k]].end(); ++it)
                if(!viz[*it]){
                    t=*it;
                    break;
                }
        if(!t) k--;
         else {
             c[++k]=t;
             viz[t]=1;
            s++;
        }
    }
    if(s<=n){
        for(int i=1;i<=n;++i)
            if(!viz[i]) {
                cont++;
                dfs(i);
            }
    }

}
int main(){
    citire();
    dfs(1);
    freopen("dfs.out","w",stdout);
        printf("%d",cont+1);
return 0;
}