You are given a string S of length N consisting of lowercase English letters. We will cut this string at one position into two strings X and Y. Here, we would like to maximize the number of different letters contained in both X and Y. Find the largest possible number of different letters contained in both X and Y when we cut the string at the optimal position.
n = int(input())
s = list(input())

maxi = 0
for i in range(1, n):
  x = 0
  for c in s[:i]:
    if c in s[i:]:
      x += 1
  maxi = max(maxi, x)
print(maxi)
n = int(input())
s = list(input())

maxi = 0
for i in range(1, n):
  x = []
  for c in s[:i]:
    if c not in x and c in s[i:]:
      x.append(c)
  maxi = max(maxi, len(x))
print(maxi)