#include<fstream>
#include<vector>
using namespace std;
vector<int> v[100005];
bool viz[100005];
void dfs(int nod)
{
    viz[nod]=1;
    for(int i=0; i<v[nod].size(); ++i)
        if(!viz[v[nod][i]])
            dfs(v[nod][i]);
}
int main()
{
    ifstream cin("dfs.in");
    ofstream cout("dfs.out");
    int n,m,ans=0;
    cin>>n>>m;
    for(int i=1; i<=n; ++i)
    {
        int x,y;
        cin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i=1; i<=n; ++i)
        if(!viz[i])
        {
            dfs(i);
            ++ans;
        }
    cout<<ans;
    return 0;
}