#include <bits/stdc++.h>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

int viz[100003],i,n,m,x,y,j;
vector <int> g[100004];

void dfs(int nod)
{
    int i,j;
    viz[nod]=1;
    ///fout<<nod<<" ";
    for(i=0;i<g[nod].size();i++)
    {
        j=g[nod][i];
        if(viz[j]==0)
        {
            dfs(j);
        }
    }
}

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