N=int(input())

P=[]
times=0
for _ in range(N):
    P.append(list(map(int,input().split()))[::-1])
    times=max(len(P[-1]),times)

#print(P)
ans=[]
for _ in range(times):
    for item in P:
        if len(item)>1:
            ans.append(item.pop(-2))
print(*ans)