#!/bin/python

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    lower=1
    upper=1
    digits=1
    special=1
    for c in password:
        if c in "0123456789":
            digits=0
        elif c in "abcdefghijklmnopqrstuvwxyz":
            lower=0
        elif c in "ABCDEFGHIJKLMNOPQRSTUVWXYZ":
            upper=0
        elif c in "!@#$%^&*()-+":
            special=0
    min_len = 0
    if len(password)<6:
        min_len+=6-len(password)
    return max(min_len,lower+upper+digits+special)
    
if __name__ == "__main__":
    n = int(raw_input().strip())
    password = raw_input().strip()
    answer = minimumNumber(n, password)
    print answer