while True:
    t=int(input())
    if t==0:break
    a=input().split()
    s1=[]
    for i in range(t):
        s=list(a[i])
        s.sort()
        s1.append("".join(s))
    s2=[]
    for i in range(t):
        if s1.count(s1[i])==1:
            s2.append(int(a[i]))
    s2.sort()
    if len(s2)==0:print("None")
    else:
        for ii in s2:
            print(ii,end=" ")
        print()