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 9.2.1) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
	char	*s = (char *)malloc(27);
	int		i = 0;
	int		j;
	s[0] = '\0';
	scanf("%s",s);  
	while(s[i]!='\0')
	{
		j=i+1;
		while(s[j] != '\0')
		{
			if (s[i] == s[j])
			{
				printf("no");
				return (0);
			}
			j++;
		}
		i++;
	}
	printf("yes");
  return (0);
}