# -*- coding: utf-8 -*-

N, = map(int, raw_input().split())

ret = 36 ** 13
for i in xrange(N):
    V, = map(str, raw_input().split())
    maxs = 0
    for v in V:
        try:
            num = int(v)
        except ValueError:
            num = ord(v) - ord('A') + 10
        maxs = max(maxs, num)
    # (maxs+1)進数として扱う
    total = 0
    for i, v in enumerate(V[::-1]):
        try:
            num = int(v)
        except ValueError:
            num = ord(v) - ord('A') + 10
        total += num * (maxs+1) ** i
    ret = min(ret, total)

print ret