#!/bin/python

import sys

def minimumNumber(n, pas):
    # Return the minimum number of characters to make the password strong
    numbers = "0123456789"
    low = "abcdefghijklmnopqrstuvwxyz"
    up = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    sp = "!@#$%^&*()-+"
    c1=c2=c3=c4=1
    for i in range(n):
        if pas[i] in numbers:
            c1=0
        elif pas[i] in low:
            c2=0
        elif pas[i] in up:
            c3=0
        elif pas[i] in sp:
            c4=0
    s=c1+c2+c3+c4
    if n+s<6:
        s+=(6-n-s)
    return s

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