#!/bin/python3
'''
numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"
'''





import sys

def minimumNumber(n, password):
    req = {'special':False, 'lower':False, 'upper':False, 'num':False}
    total = 0
    for char in password:
        if req['special'] and req['lower'] and req['upper'] and req['num']:
            break
        if ord(char) >= 33 and ord(char) <= 45:
            req['special'] = True
        if ord(char) >= 97 and ord(char) <= 122:
            req['lower'] = True
        if ord(char) >= 65 and ord(char) <= 90:
            req['upper'] = True 
        if ord(char) >= 48 and ord(char) <= 57:
            req['num'] = True
          
    for key, value in req.items():
        if not value:
            total+=1
    if(total+n < 6):
        return (6 - (total+n)) + total
    else:
        return total
        
    
        

if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)