import string

table = string.digits + string.ascii_uppercase

res = float("inf")

for _ in range(int(input())):
    S = input()
    m = max([table.find(s) + 1 for s in S])
    res = min(res, sum([table.find(s) * pow(m, i) for i, s in enumerate(S[::-1])]))

print(res)