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 (1.15.1) (judge verdict: Accepted)

use std::io;

fn read_line()-> String {
    let mut s = String::new();
    let _ = io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

fn main() {
	let S = read_line();
	let S = S.split("").collect::<Vec<&str>>();
	let mut flag:bool = true;
	for i in 1..(S.len()-1) {
		for j in 1..(S.len() - 1) {
			if i == j {
				continue;
			}
			if S[i] == S[j].to_string() {
				flag = false;
				break;
			}
 		}
	}
	if flag == true {
		println!("yes");
	}else{
		println!("no");
	}
}