n = int(input())

A = [list(input()) for i in range(n)]


d = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"


def calc(s: str):
    mx = max(s)
    res = 0
    for c in s:
        res *= d.find(mx) + 1
        res += d.find(c)
    return res


print(min(map(calc, A)))