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)

fn main() {
	proconio::input!{
		mut cs: proconio::marker::Chars,
	}

	let len1 = cs.len();
	cs.sort();
	cs.dedup();
	if len1 == cs.len() {
		println!("yes");
	}
	else {
		println!("no");
	}
}