N = int(input())
V = [input().rstrip() for _ in range(N)]
digit = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
MIN = pow(36, 12) - 1
for v in V:
    MAX = 1
    for w in v:
        MAX = max(MAX, digit.index(w))
    BASE = MAX + 1
    VAL = 0
    v = v[::-1]
    for i in range(len(v)):
        VAL += pow(BASE, i) * digit.index(v[i])
    #print(VAL)
    MIN = min(MIN, VAL)
print(MIN)