#include <iostream>
#include <fstream>

using namespace std;

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

const int NMAX = 1e6;
int n,m;
int used[NMAX];
vector <int> graf[NMAX];

void read()
{
    in>>n>>m;
    for(int i=1; i<=n; i++)
    {
        int x,y;
        in>>x>>y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
}
void dfs(int node)
{
    used[node]=1;
    for(int i=0; i<(int)graf[node].size(); i++)
    {
        if(used[graf[node][i]]==0)
            dfs(graf[node][i]);
    }
}
void solve()
{
    int sol=0;
    for(int i=1; i<=n; i++)
    {
        if(used[i]==0)
        {
            sol++;
            dfs(i);
        }
    }
    out<<sol;
}
int main()
{
    read();
    solve();
}