N=int(input())
P=[list(map(int,input().split())) for _ in range(N)]
P_num=max([P[i][0] for i in range(N)])
ans=[]
for x in range(1,P_num+1):
    for y in range(N):
        if len(P[y])==1:
            continue
        ans.append(P[y][1])
        P[y].pop(0)
print(*ans)