#!/bin/python

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 = "!@#$%^&*()-+"
    types=[1,1,1,1]
    for i in password:
        if i in numbers:
            types[0]=0
            continue
        elif i in lower_case:
            types[1]=0
            continue
        elif i in upper_case:
            types[2]=0
            continue
        elif i in special_characters:
            types[3]=0
    if (sum(types)+n)>=6:
            return sum(types)
    return (6-n)
    

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