package main
import "fmt"

func main() {
    var n int
    fmt.Scanf("%d", &n)
    var str string
    fmt.Scanf("%s", &str)
    special := []byte{'!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '-', '+'}
    hasLower, hasUpper, hasDigit, hasSpecial := false, false, false, false
    for i := 0; i < len(str); i++ {
        if str[i] >= 'a' && str[i] <= 'z' {
            hasLower = true
        } else if str[i] >= 'A' && str[i] <= 'Z' {
            hasUpper = true
        }else if str[i] >= '0' && str[i] <= '9' {
            hasDigit = true
        } else {
            for k := 0; k < len(special); k++ {
                if str[i] == special[k] {
                    hasSpecial = true
                }
            }
        }
    }
    need := 0
    if !hasLower {
        need++
    }
    if !hasUpper {
        need++
    }
    if !hasDigit {
        need++
    }
    if !hasSpecial {
        need++
    }
    if 6 - len(str) > need {
        need = 6 - len(str)
    }
    fmt.Print(need)
}