#!/bin/python3

import sys

def minimumNumber(n, s):
    # Return the minimum number of characters to make the password strong
    n = "0123456789"
    lc ="abcdefghijklmnopqrstuvwxyz"
    uc= "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    sc ="!@#$%^&*()-+"
    (c,c1,c2,c3)=(0,0,0,0)
    co=0
    for i in s:
        if i in n and c<1:
            c=1
            co +=1
        elif i in lc and c1<1:
            c1=1
            co +=1
        elif i in uc and c2<1:
            c2=1
            co +=1
        elif i in sc and c3<1:
            c3=1
            co +=1
    l=6-len(s)
    lm=4-co
    if len(s)<6 and l>lm:
        return l
    else:
        co =4-co
        return co
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)