import Foundation

// Enter your code here 
let n = Int(readLine()!)!
let str = readLine()!
var count = 0
var numNeeded = 0

let specials = CharacterSet.init(charactersIn: "!@#$%^&*()-+")

if n < 6 {
  numNeeded = 6 - n
}

if str.rangeOfCharacter(from: specials) == nil {
    count+=1
}

if str.rangeOfCharacter(from: CharacterSet.decimalDigits) == nil {
    count+=1
}

if str.rangeOfCharacter(from: CharacterSet.uppercaseLetters) == nil {
    count+=1
}

if str.rangeOfCharacter(from: CharacterSet.lowercaseLetters) == nil {
    count+=1
}

if numNeeded > count {
  print(numNeeded)
} else {
  print(count)
}