#!/bin/python3

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special = "!@#$%^&*()-+"
    
    
    used = [0, 0, 0, 0]
    
    for char in password:
        if char in numbers: used[0] = 1
        if char in lower_case: used[1] = 1
        if char in upper_case: used[2] = 1
        if char in special: used[3] = 1
        
    ans = 4
    for num in used:
        ans -= num
        
    if ans + n < 6: ans += 6 - ans - n
        
    return ans
        
    
    
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)