#!/bin/python

import sys

def minimumNumber(n, password):
    s = password
    ans = 0
    lower,upper,special,digit = True,True, True, True
    for x in s:
        #print x
        if x.islower():
            #print 'low'
            lower = False
        if x.isupper():
            #print 'up'
            upper = False
        if x.isdigit():
            #print 'dig'
            digit = False
        if x in '!@#$%^&*()-+':
            #print 'spec'
            special = False
    return max(lower + upper + special + digit, 6 - len(s))

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