#include <iostream>
#include <queue>
using namespace std;
const int N=1e5;
bitset<N+1>viz;
vector<int>a[N+1];
void dfs(int x)
{
    viz[x]=1;
    for(auto y:a[x])
    {
        if(!viz[y])
            dfs(y);
    }
}
int main()
{
    ifstream in(dfs.in);
    ofstream out(dfs.out);
    int n,m,nc=0;
    in>>n>>m;
    for(int i=0;i<n;i++)
    {
        int x,y;
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for(int i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            nc++;
            dfs(i);
        }
    }
    out<<nc;
    in.close();
    out.close();
    return 0;
}