#!/bin/python

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    flag = 0
    count = 0
    
    length = len(password);
    for i in lower_case:
        if(i in password):
            flag = 1
            break
    if(flag ==0):
        count +=1
        
    flag = 0    
    for i in upper_case:
        if(i in password):
            flag = 1
            break
            
    if(flag == 0):
        count +=1
    flag = 0    
    for i in special_characters:
        if(i in password):
            flag = 1
            break
            
    if(flag ==0):
        count +=1        
    flag = 0
    
    for i in numbers:
        if(i in password):
            flag = 1
            break
    if(flag ==0):
        count +=1
    flag = 0
    
    if(length + count >=6):
        return count
    else:
        return 6-(length) 
            
    # Return the minimum number of characters to make the password strong

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