/// Craciun Catalin
///  DFS
#include <iostream>
#include <cstring>
#include <fstream>
#include <vector>

#define NMax 100005

using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

int n, m;
vector<int> A[NMax];
bool V[NMax];
int comp = 0;

void dfs (int nod) {

    V[nod] = true;
    for (int i=0;i<A[nod].size();i++) {
        if (!V[A[nod][i]])
            dfs(A[nod][i]);
    }
}

int main() {

    f>>n>>m;
    for (int i=1;i<=n;i++) {
        int x, y;
        f>>x>>y;
        A[x].push_back(y);
        A[y].push_back(x);
    }

    memset(V, false, sizeof(V));
    for (int i=1;i<=n;i++)
        if (!V[i]) {
            comp++;
            dfs(i);
        }

    g<<comp<<'\n';

    f.close(); g.close();

    return 0;
}