#!/bin/python3

import sys

def minimumNumber(n, password):
    spe = "!@#$%^&*()-+"
    s = 0
    l = 0
    u = 0
    d = 0
    tot = 0
    for i in password:
        k = ord(i)
        if i in spe:
            s += 1
        elif k >= 65 and k <= 90:
            u += 1
        elif k >= 97 and k <= 122:
            l += 1
        elif k >= 48 and k <= 57:
            d += 1
    if s == 0:
        tot += 1
    if u == 0:
        tot += 1
    if l == 0:
        tot += 1
    if d == 0:
        tot += 1
    #print(tot)
    if n < 6:
        total = 6 - n
        if total >= tot:
            return total
        else:
            return tot
    else:
        return tot

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