Python3 代码

while True:
    n = int(input())
    if n == 0:
        break

    s = [""] * 200
    s_len = n

    mlen = 200
    ms = ""
    for i in range (n):
        s[i] = input()
        if mlen > len(s[i]):
            mlen = len(s[i])
            ms = s[i]

    found = False

    for j in range (mlen):
        is_success = True
        ms2 = ms[j:]
        for k in range (s_len):
            if s[k][len(s[k]) - mlen + j:] != ms2:
                is_success = False
        if is_success:
            found = True
            print (ms2)
            break

    if not found:
        print ("")