#include<bits/stdc++.h>
#define M 100003
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
vector<int>lista[M];


int n,m,viz[M],nr;

void citire()
{
    int i,x,y;
    fin>>n>>m;
    for(i=1;i<=n;i++)
    {
        fin>>x>>y;
        lista[x].push_back(y);
        lista[y].push_back(x);
    }
}

void dfs(int node)
{
    viz[node]=1;

    for(auto x:lista[node])
    {
        if(viz[x]==0)
            dfs(x);
    }

}

int main()
{
    citire();
    for(int i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            nr++;
            dfs(i);
        }
    }
    fout<<nr;
    return 0;
}