#!/bin/python

import sys
import re

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    #n = number of char
    count=0
    min = None
    if n==0:
        return 6
    if n==1:
        return 5
    if n==2:
        return 4
    if n < 7:
        min = 6-n
    digit = re.search(r"\d", password)
    uppercase = re.search(r"[A-Z]", password)
    lowercase = re.search(r"[a-z]", password)
    symbol = re.search(r"[!@#$+%\-^&*()]", password)
    if not digit:
        count+=1
    if not uppercase:
        count+=1
    if not lowercase:
        count+=1
    if not symbol:
        count+=1
    if min and count < min:
        return min
    return count

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