#include "iostream"

int *Merge(const int *a, const int *b, const int &k, const int &m) {
  int i = 0, j = 0, p = 0;
  int *c = new int[m + k];
  while (i < k && j < m) {
    if (a[i] <= b[j]) {
      c[p] = a[i];
      ++i;
      ++p;
    } else {
      c[p] = b[j];
      ++j;
      ++p;
    }
  }
  while (i < k) {
    c[p] = a[i];
    i++;
    p++;
  }
  while (j < m) {
    c[p] = b[j];
    j++;
    p++;
  }
  return c;
}

int main() {
  int n, k, m = 0;
  std::cin >> n;
  int *c = new int[1];
  for (int i = 0; i < n; ++i) {
    std::cin >> k;
    int *a = new int[k];
    for (int j = 0; j < k; ++j) {
      std::cin >> a[j];
    }
    int *temp = Merge(a, c, k, m);
    delete[] c;
    c = temp;
    m = m + k;
    delete[] a;
  }
  for (int i = 0; i < m; ++i) {
    std::cout << c[i] << ' ';
  }
  delete[] c;
}