#!/bin/python3

import sys

def minimumNumber(n, password):
    numbers = set("0123456789")
    lower_case = set("abcdefghijklmnopqrstuvwxyz")
    upper_case = set("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
    special_characters = set("!@#$%^&*()-+")
    
    l=False; L=False;U=False; S=False; N=False;
    if n >= 6:
        l=True
    if len(lower_case & set(password)) >=1:
        L=True
    if len(upper_case & set(password)) >=1:
        U=True
    if len(special_characters & set(password)) >=1:
        S=True
    if len(numbers & set(password)) >=1:
        N=True
    count=0 
    count1=0
    pwd=set(password)
    if l is True:
        if L is False:
            count+=1
        if U is False:
            count+=1
        if S is False:
            count+=1
        if N is False:
            count+=1
        return count
    else:
        count=6-n
        if L is False:
            count1+=1
        if U is False:
            count1+=1
        if S is False:
            count1+=1
        if N is False:
            count1+=1
        r=count1-count 
        if r >0:
            count+=r
        return count
        

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