#!/bin/python3

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


def minimumNumber(n, password):
    N = False
    L = False
    U = False
    S = False
    
    for i in password:
        if i in special_characters:
            S = True
        if i in numbers:
            N = True
        if i in lower_case:
            L = True
        if i in upper_case:
            U = True
    ans = [S, N, L, U]
    ct = 0
    for i in ans:
        if i == True:
            ct +=1
    

    #if int(n)<6:
        #return (6-n)
    y = 0
    z = 4 - ct
    if int(n)+z<6:
        return (6-int(n))

  
    return(z)
    # Return the minimum number of characters to make the password strong

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