n=int(input())
v=[list(input()) for i in range(n)]

c=[chr(i) for i in range(65, 65+26)]
l=[str(i) for i in range(10)]+c

ans=[]
for i in range(n):
  x=v[i]
  y=-1
  for j in range(len(x)):
    y=max(y,l.index(x[j]))
  y+=1
  x.reverse()
  z=0
  for j in range(len(x)):
    z+=l.index(x[j])*y**j
  ans.append(z)
print(min(ans))