N=int(input())

Al=["0","1","2","3","4","5","6","7","8","9","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"]
Dic={}
for i in range(36):
    Dic[Al[i]]=i
#print(Dic)

F="0000000000000"

Dim=0
L=[]
for i in range(N):
    s=input()
    s=F+s
    s=s[-12:]
    for j in range(len(s)):
        Dim=max(Dim,Dic[s[j]])
    L.append(s)
#print(Dim)

ans=10**30
for i in L:
    cnt=0
    for j in range(12):
        cnt+=Dic[i[j]]*((Dim+1)**(11-j))
    ans=min(ans,cnt)
print(ans)