N = int(input())
queue = []
for i in range(N):
    k, *a = map(int, input().split())
    queue.append(a)

ans = []
while sum([len(q) for q in queue]) > 0:
    for i in range(N):
        if len(queue[i]) > 0:
            ans.append(queue[i].pop(0))

print(*ans)