#include <fstream>
#include <queue>
#include <vector>


using namespace std;

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

int v[100001],n,m,comp;
vector <int> M[100001];
queue <int> Q;

void bfs (int x)
{
    v[x]=1;
    Q.push(x);
    while (!Q.empty())
    {
        for (auto i:M[Q.front()])
            if (!v[i]){
                v[i]=1;
                Q.push(i);
            }
        Q.pop();
    }
}

int main()
{
    cin>>n>>m;
    for (int i=1; i<=m; ++i)
    {
        int x,y;
        cin>>x>>y;
        M[x].push_back(y);
        M[y].push_back(x);
    }
    for (int i=1; i<=n; ++i)
        if (!v[i]){
            comp++;
            bfs(i);
        }
    cout<<comp;

    return 0;
}