#!/bin/python3

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    res2 = 4
    for lower in lower_case:
        if lower in password:
            res2 -= 1
            break
    
    for lower in upper_case:
        if lower in password:
            res2 -= 1
            break
    
    for lower in special_characters:
        if lower in password:
            res2 -= 1
            break
    
    for lower in numbers:
        if lower in password:
            res2 -= 1
            break
    res1 = 6 - (n+res2)
    if res1 < 0:
        return res2
    else:
        return res1 + res2

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