Problem:
Score : 200 points

Problem Statement

You are given a string S consisting of lowercase English letters. Determine whether all the characters in S are different.

Constraints

2 ≤ |S| ≤ 26, where |S| denotes the length of S.

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If all the characters in S are different, print yes (case-sensitive); otherwise, print no.

Sample Input 1

uncopyrightable

Sample Output 1

yes

Sample Input 2

different

Sample Output 2

no

Sample Input 3

no

Sample Output 3

yes

Solution in Scala (2.11.7) (judge verdict: Accepted)


import java.util.Scanner

object Main extends App {
  val sc = new Scanner(System.in)

  val str = sc.next()

  if (str.toStream.toSet.size == str.size) {
    println("yes")
  } else {
    println("no")
  }
}