package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
	"strings"
)

func main() {
    numbers := "0123456789"
    lower_case := "abcdefghijklmnopqrstuvwxyz"
    upper_case := "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters := "!@#$%^&*()-+"
    
    scanner := bufio.NewScanner(os.Stdin)
    
    scanner.Scan()
	n, _ := strconv.Atoi(scanner.Text())
    
    scanner.Scan()
	password := scanner.Text()
    
    digit := 0
    lower := 0
    upper := 0
    special := 0
    for i:=0 ; i<n ; i++ {
        c := password[i:i+1]
        
        if strings.Contains(numbers, c) {
            digit = 1
        }
        if strings.Contains(lower_case, c) {
            lower = 1
        }
        if strings.Contains(upper_case, c) {
            upper = 1
        }
        if strings.Contains(special_characters, c) {
            special = 1
        }
    }
    
    sum := 4 - (digit + lower + upper + special)
    diff := 0
    if n < 6 {
        diff = 6 - n
    }
    
    if sum > diff {
        diff = sum
    }
    
    fmt.Println(diff)
}