#!/bin/python3

import sys
import re

def minimumNumber(n, password):
    req = 4
    digit = False
    lower = False
    upper = False
    special = False
    for char in password:
        if char in "0123456789":
            digit = True
        if char in "abcdefghijklmnopqrstuvwxyz":
            lower = True
        if char in "ABCDEFGHIJKLMNOPQRSTUVWXYZ":
            upper = True
        if char in "!@#$%^&*()-+":
            special = True
    if (digit == True):
        req -= 1
    if (lower == True):
        req -= 1
    if (upper == True):
        req -= 1
    if (special == True):
        req -= 1
    if (n >= 6):
        return req
    else:
        return max(req, 6-n)

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