#include <fstream>
#include <vector>
#include <bitset>
#define pb push_back
using namespace std;

bitset <1000005> viz;
vector <int> a[100005];
int n, m, sol;

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

void dfs(int);

int main()
{
    cin>>n>>m;
    for(int i = 1; i <= n ; ++i)
    {
        int x, y;
        cin>>x>>y;
        a[x].pb(y);
        a[y].pb(x);
    }
    for(int i = 1 ; i <= n ; ++i)
        if(!viz[i])
            ++sol, dfs(i);
    cout<<sol<<"\n";
    cin.close();
    cout.close();
    return 0;
}

void dfs(int node)
{
    viz[node]=1;
    for(int i = 0; i <a[node].size(); ++i)
        if(!viz[a[node][i]])
            dfs(a[node][i]);
}