#!/bin/python3

import sys


def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    l_num=0
    l_low=0
    l_upp=0
    l_special=0
    count=0
    l_diff=n-6
    for i in password:
            if i in "0123456789":
                l_num=1
            if i in "abcdefghijklmnopqrstuvwxyz":
                l_low=1
            if i in "ABCDEFGHIJKLMNOPQRSTUVWXYZ":
                l_upp=1
            if i in "!@#$%^&*()-+":
                l_special=1
     
    if not l_num:
        count +=1
    if not l_low:
        count += 1
    if not l_upp :
        count += 1
    if not l_special:
        count += 1
        
    if l_diff<0:
        l_diff=-1*l_diff
        
    if n>=6:
        if count:
            return count
        else:
            return 0
    else:
        if l_diff>=count:
            return l_diff
        else:
            return count

     
    
    
    
    

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