#!/bin/python3

import sys

def minimumNumber(n, password):
    count = 0
    n2=0;
    l=0;
    u=0;
    s=0;
    numbers = ['0','1','2','3','4','5','6','7','8','9']
    lower_case = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
    upper_case = ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z']
    special_characters = ['\'','!','@','#','$','%','^','&','*','(',')','-','+']
    for x in password:
        if x in numbers and n2==0:
            
            n2=1
        elif x in lower_case and l==0:
            
            l=1
        elif x in upper_case and u==0:
            u=1
        elif x in special_characters:
            s=1
    if n2==0:
        count = count+1
    if l==0:
        count = count+1
        
    if u==0:
        count = count+1
    if s==0:
        count = count+1
    if n<6:
        if count < (6-n):
            count = 6-n
    return count

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