N = int(input())
Vs = [input() for _ in range(N)]
dic = {}
for i in range(10):
    dic[str(i)] = i
for i in range(26):
    dic[chr(65 + i)] = 10 + i

ans = 36 ** 12
for V in Vs:
    D = dic[max(list(V))] + 1
    tmp = 0
    for v in V:
        tmp *= D
        tmp += dic[v]
    ans = min(ans, tmp)
print(ans)