#!/bin/python3

import sys

def minimumNumber(n, password):
    s=password
    sc="!@#$%^&*()-+"
    f1=f2=f3=f4=0
    for ele in s:
        if ele.islower():
            f1=1
        if ele in sc:
            f2=1
        if ele.isupper():
            f3=1
        if ele>='0' and ele<='9':
            f4=1
    extra=4
    extra-=(f1+f2+f3+f4)
    if len(s)+extra>=6:
        return extra
    else:
        return 6-len(s)
    
   
        
    
    
    # Return the minimum number of characters to make the password strong

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