def base(s):
    
    def ord2(x):
        a = ord(x)
        if  a <= 57 :
            a -= 48
        else:
            a -= 55
        return a

    ordlist = [ ord2(s[i]) for i in range(len(s))]

    digit = max(ordlist) + 1

    ordlist = [ ordlist[i] * (digit ** (len(s) - i - 1) ) for i in range(len(s))]

    return sum(ordlist)

n = int(input())
anslist = [0]*n


for i in range(n):
    s = input()
    anslist[i] = base(s)


print(min(anslist))