def decode(S):
    d=max([X.index(s) for s in S])+1

    b=1
    A=0
    for s in S[::-1]:
        A+=b*X.index(s)
        b*=d
    return A

import sys
from string import ascii_uppercase as X

input=sys.stdin.readline
X="0123456789"+X

N=int(input())
M=float("inf")
for _ in range(N):
    M=min(M,decode(input()[:-1]))
print(M)