numbers = '0123456789'
lower_case = 'abcdefghijklmnopqrstuvwxyz'
upper_case = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
special_characters = '!@#$%^&*()-+'

def solve(n, pw):
  a, b, c, d = 1, 1, 1, 1
  q = max(0, 6 - n)
  for ch in pw:
    if ch in numbers: a = 0
    if ch in lower_case: b = 0
    if ch in upper_case: c = 0
    if ch in special_characters: d = 0
  return max(q, a + b + c + d)

n = int(raw_input())
pw = raw_input().strip()
print(solve(n, pw))