#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong

    

    # Uses python 3
    # Written by: Stephen Jonker
    # Written on: Thursday 02 Nov 2017 


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

    # print(numbers)

    #n = int(input())
    #string = input() 

    string = password
    
    #print("n:", n)
    #print("str", string)

    flag = 0
    nflag = 0
    uflag = 0 
    lflag = 0 
    sflag = 0

    addChars = 0

    theLen = len(string)
    if theLen <= 6:
        addChars = 6 - theLen
        #print("Must add length", addChars) 

    for c in string:
        if c in numbers:
            nflag = 1 
            #print("num")

    for c in string:
        if c in lower_case:
            lflag = 1
            #print("lower error")

    for c in string:
        if c in upper_case:
            #print("upper error")
            uflag = 1

    for c in string:
        if c in special_characters:
            sflag = 1
            #print("special errr")

    flag = nflag + lflag + uflag + sflag

    need = 4 - flag

    #print("Found: ", flag)
    #print("Need: ", 4 - flag)
    #print("error:", addChars)

    if addChars > need:
        return addChars
        # length error
    else: 
        return need
   
    
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)