import sys
input=lambda: sys.stdin.readline().rstrip()
n=int(input())
def f(S):
  A=[]
  for s in S:
    if 65<=ord(s)<=90:
      A.append(ord(s)-55)
    else:
      A.append(int(s))
  m=max(A)+1
  ret=0
  keta=0
  for a in A[::-1]:
    ret+=a*(m**keta)
    keta+=1
  return ret
ans=float("inf")
for _ in range(n):
  ans=min(ans,f(input()))
print(ans)