#!/bin/python3

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    num=0
    l=0
    u=0
    s=0
    for i in password : 
        if i in numbers : 
            num=num+1
        elif i in lower_case : 
            l=l+1
        elif i in upper_case : 
            u=u+1
        else : 
            s=s+1
    n1=n
    if num==0 : 
        n1=n1+1
    if l==0 : 
        n1=n1+1
    if u==0 : 
        n1=n1+1
    if s==0 : 
        n1=n1+1
    if n1<6 : 
        return(n1-n+6-n1)
    return(n1-n)

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