题目1526：朋友圈

#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

const int N = 100010;

int p[N];

int find(int x);

int main()
{
    int n, m;
    int u, v;

    #ifndef ONLINE_JUDGE
        ifstream cin("d:\\OJ\\uva_in.txt");
    #endif // ONLINE_JUDGE

    while (cin >> n, n) {
        cin >> m;

        memset(p, -1, sizeof(int) * n);
        for (int i = 0; i < m; i++) {
            cin >> u >> v;
            u--, v--;
            int pu = find(u), pv = find(v);
            if (pu != pv) {
                p[pv] = pu;
            }
        }

        int ans = 0;
        for (int i = 0; i < n; i++) {
            if (p[i] < 0) ans++;
        }
        cout << ans << endl;
    }
    return 0;
}

int find(int x)
{
    return p[x] < 0 ? x : (p[x] = find(p[x]));
}