#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int findfa(vector<int>& fa, int x) {
    if (fa[x] == x) return x;
    return fa[x] = findfa(fa, fa[x]);
}

void mergefa(vector<int>& fa, int a, int b) {
    a = findfa(fa, a);
    b = findfa(fa, b);
    if (a != b) fa[b] = a;
}

int main() {
    int n, m;
    cin >> n >> m;

    vector<int> fa(m + 1);
    for (int i = 1; i <= m; i++) fa[i] = i;

    for (int i = 0; i < n; i++) {
        int k;
        cin >> k;

        int first, wzpjsylai;
        cin >> first;
        for (int j = 1; j < k; j++) {
            cin >> wzpjsylai;
            mergefa(fa, first, wzpjsylai);
        }
    }

    // 先路径压缩
    for (int i = 1; i <= m; i++) {
        fa[i] = findfa(fa, i);
    }

    const int INF = 1e9;
    vector<int> mn(m + 1, INF);

    // 统计每个连通块最小值
    for (int i = 1; i <= m; i++) {
        mn[fa[i]] = min(mn[fa[i]], i);
    }

    vector<int> ans;
    for (int i = 1; i <= m; i++) {
        if (mn[i] != INF) ans.push_back(mn[i]);
    }

    sort(ans.begin(), ans.end());

    for (int i = 0; i < (int)ans.size(); i++) {
        if (i) cout << ' ';
        cout << ans[i];
    }
    cout << '\n';

    return 0;
}