#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

int main() {
  int N;
  scanf("%d", &N);
  vector< queue<int> > A(N);
  int q = 0;
  for (int i = 0; i < N; ++i) {
    int P;
    scanf("%d", &P);
    q += P;
    for (int j = 0; j < P; ++j) {
      int a;
      scanf("%d", &a);
      A[i].push(a);
    }
  }

  while (q > 0) {
    for (int i = 0; i < N; ++i) {
      if (!A[i].empty()) {
	int next = A[i].front(); A[i].pop();
	if (q == 1) cout << next << endl;
	else cout << next << " ";
	q--;
      }
    }
  }
  return 0;
}