#include <bits/stdc++.h>
#define DM 100005
#define pb push_back
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n,m,x,y,comp;
bitset<DM>viz;
vector<int>v[DM];

void dfs(int nod){
    viz[nod]=1;
    for(auto i:v[nod]) if(!viz[i])
        dfs(i);
}

int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;++i){
        fin>>x>>y;
        v[x].pb(y);
        v[y].pb(x);
    }
    for(int i=1;i<=n;++i) if(!viz[i]){
        comp++;
        dfs(i);
    }
    fout<<comp;
    return 0;
}