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 Rust (1.42.0) (judge verdict: Accepted)

use itertools::Itertools;

fn main() {
    proconio::input! {
    a:String,
  }
    let e=['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',];
    let mut v=[0;26];
    let a=a.chars().collect_vec();
    for i in 0..a.len() {
        for j in 0..26 {
            if a[i]==e[j] {
                if v[j]==1{println!("no");std::process::exit(0)}
                v[j]=1;
            }
        }
    }
    println!("yes")
}