n=int(input())

ls=[int(x) for x in input().split()]

ls2=sorted(ls,reverse=True)

flag = True
res=0
if ls2[0] == 0:
    flag=False
    print('0' * len(ls2))
if flag:
    if ls2[-1] == 0:
        print(*ls2,sep='')
    else:
        print(-1)