#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    cond1=0;
    cond2=1;
    cond3=1;
    cond4=1;
    cond5=1;
    if n>=6:
        cond1=0;
    else:
        cond1=6-n;
    for char in password:
        if char in numbers:
            cond2=0;
        if char in lower_case:
            cond3=0;
        if char in upper_case:
            cond4=0;
        if char in special_characters:
            cond5=0;
    if cond2+cond3+cond4+cond5>cond1:
        return cond2+cond3+cond4+cond5
    return cond1
        

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