#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    count=0
    if  password.isalnum():
        count=count+1
    upperflag=0
    lowerflag=0
    digitflag=0
    for i in password:
        if i.isupper():
            upperflag=1
        elif i.islower():
            lowerflag=1
        elif i.isdigit():
            digitflag=1
    if upperflag==0:
        count+=1
    if lowerflag==0:
        count+=1
    if digitflag==0:
        count+=1
    if n<6:
        if count+n<6:
            return 6-n
        else:
            return count
    else:
        return count
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)