#include<iostream>
#include<fstream>
#include<vector>
#define nmax 200000
using namespace std;
ifstream in("dfs.in");
ofstream out("dfs.out");
vector<int> g[nmax];
int m[nmax];
void dfs(int x){
        { m[x]=1;
             for(vector<int>::iterator it=g[x].begin(); it!=g[x].end();it++)
            if(m[*it]==0)
            dfs(*it);
        }
}
int main(){
    int n,p,i,a,b,x,c=0;
    in>>n>>p;
    for(i=1;i<=p;i++)
    { in>>a>>b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    for(i=1;i<=n;i++) if(!m[i]) { dfs(i); c++; }
    out<<c<<'\n';
    return 0;



}