#!/bin/python

import sys
numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"

def minimumNumber(n, password):
    
    t=0
    l=0
    u=0
    s=0
    ans=0
    for k in password:
        if k in numbers:
            t+=1
        elif k in lower_case:
            l+=1
        elif k in upper_case:
            u+=1
        elif k in special_characters:
            s+=1
    
    if s==0:
        ans+=1
    if t==0:
        ans+=1
    if u==0:
        ans+=1
    if l==0:
        ans+=1
    
    if ans+n>=6:
        return ans
    else:
        return 6-n
            
            

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