import numpy as np
b = {}#辞書
for i in range(10):
    b[str(i)]=i
for i,alpha in enumerate(["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]):
    b[alpha]=i+10
    
V=[]
N=int(input())
for i in range(N):
    V.append(input())

def cal(v):
    temp=1
    for i in v:
        if(b[i]>temp):
            temp=b[i]
    temp+=1
    
    sum=0
    count=0
    for i in reversed(range(len(v))):
        sum+=b[v[i]]*(temp**count)
        count+=1
    return sum

mi=[]
for v in V:
    mi.append(cal(v))

print(min(mi))