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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int main()
{
	int i, j, ans = 0;
	char s[27];

	scanf("%s", s);

	for (i = 0; i < 26; i++){
		for (j = 1 + i; j < 27; j++){
			if (s[i] == s[j])
				ans++;
		}
	}

	if (ans != 0)
		printf("no");
	else
		printf("yes");

	return 0;
}