// @EXPECTED_RESULTS@: ACCEPTED, TIME_LIMIT_EXCEEDED
import java.util.*;

public class MikeTranscribedScanner {
    private static final long BASE = 1000000007;

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int L = (int) Math.sqrt(n);
        List<List<Integer>> sets = new ArrayList<>();

        for (int i = 0; i < n; i++) {
            int k = scanner.nextInt();
            List<Integer> set = new ArrayList<>();
            for (int j = 0; j < k; j++) {
                set.add(scanner.nextInt()); // This is slow.
            }
            sets.add(set);
        }

        Map<Long, Integer> pairs = new HashMap<>();
        for (int i = 0; i < n; i++) {
            if (sets.get(i).size() <= L) {
                Collections.sort(sets.get(i));
                for (int j1 = 0; j1 < sets.get(i).size(); j1++) {
                    for (int j2 = j1 + 1; j2 < sets.get(i).size(); j2++) {
                        long x = sets.get(i).get(j1) + BASE * sets.get(i).get(j2);
                        if (pairs.containsKey(x)) {
                            System.out.println(sets.get(i).get(j1) + " " + sets.get(i).get(j2) + " " + (pairs.get(x) + 1) + " " + (i + 1));
                            return;
                        }
                        pairs.put(x, i);
                    }
                }
            } else {
                Set<Integer> xs = new HashSet<>(sets.get(i));
                for (int j = 0; j < n; j++) {
                    if (i != j) {
                        List<Integer> overlap = new ArrayList<>();
                        for (Integer x : sets.get(j)) {
                            if (xs.contains(x)) {
                                overlap.add(x);
                            }
                        }
                        if (overlap.size() >= 2) {
                            System.out.println(overlap.get(0) + " " + overlap.get(1) + " " + (j + 1) + " " + (i + 1));
                            return;
                        }
                    }
                }
            }
        }
        System.out.println("impossible");
    }
}