#!/bin/python3

import sys

def minimumNumber(n, password):
    num,l,u,c = 1,1,1,1
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    for i in range(n):
        if(password[i] in numbers and num==1):
            num = 0
        if(password[i] in lower_case and l==1):
            l = 0
        if(password[i] in upper_case and u==1):
            u = 0
        if(password[i] in special_characters and c==1):
            c = 0
        if(num==0 and l==0 and u==0 and c==0):
            break
    ans = num+l+u+c
    if (n>6 or n+ans>6):
        return ans
    else:
        return 6-n
    
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)