#!/bin/python

import sys

numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"

def minimumNumber(n, password):
    too_add = 0
    num = 1
    lc = 1
    uc =1
    sc = 1
    for c in password:
        if c in lower_case:
            lc =0
        if c in upper_case:
            uc =0
        if c in numbers:
            num =0
        if c in special_characters:
            sc =0
    too_add += num + lc + uc +sc
    return(max(too_add,(6-n)))

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