#include <iostream>
#include <vector>
#include <fstream>

using namespace std;

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

#define dim 100016
vector <int> Node[dim];

bool vizitat[dim];
int cnt , n , m , x ,y;

void DFS( unsigned int nod )
{
    vizitat[nod] = true;
    for (unsigned int i = 1 ; i <= Node[nod].size() ; ++i)
    {
        int next = Node[nod][i];
        if(!vizitat[next])
            DFS(next);
    }
}
void Read()
{
    fin >> n >> m; /// n - noduri , m - muchii

    for ( int i = 1 ; i <= n ; i++)
    {
        fin >> x >> y;
        Node[x].push_back(y);
        Node[y].push_back(x);
    }

    for ( int i = 1 ; i <= n ; ++i)
    {
        if (!vizitat[i])
        {
            cnt++;
            DFS(i);
        }
    }
}
int main()
{
    Read();
    fout << cnt;
    return 0;
}