#!/bin/python

import sys

def minimumNumber(n, password):
    special_characters = "!@#$%^&*()-+"
    num = False; lower = False; upper = False; symbol = False
    for char in password:
        asc = ord(char)
        if 48 <= asc and asc <= 57:
            num = True
        elif 65 <= asc and asc <= 90:
            upper = True
        elif 97 <= asc and asc <= 122:
            lower = True
        elif char in special_characters:
            symbol = True
    extra = 0
    if not num:
        extra += 1
    if not lower:
        extra += 1
    if not upper:
        extra += 1
    if not symbol:
        extra += 1
    if len(password) + extra < 6:
        return 6 - len(password)
    else:
        return extra
       

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