#include <fstream>
#include <bitset>
#include <vector>

using namespace std;

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

int n, m, x, y, k;
bitset<100005> v;
vector<int> a[100005];

int dfs(int nod)
{
    v[nod] = 1;
    vector<int> :: iterator it;
    for(it = a[nod].begin(); it != a[nod].end(); ++ it)
        if(!v[*it]) dfs(*it);
}

int main()
{
    F >> n >> m;
    for( int i = 1; i <= n; ++ i )
    {
        F >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for(int i = 1; i <= n; ++ i)
        if(!v[i]) dfs(i), ++k;
    G << k;
    return 0;
}