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>

int varied(char *str)
{
	int i;
	int j;
	char temp;
	int flag;

	i = 0;
	flag = 0;
	while (str[i])
	{
		j = i + 1;
		while (str[j])
		{
			if (str[i] == str[j])
			{
				flag = 1;
				return (1);
			}
			j++;
		}
		i++;
	}
	return (0);
}

int		main(void)
{
	char s[27];
	int res;

	scanf("%s", s);
	res = varied(s);
	if (res == 1)
	{
		printf("no\n");
	}
	else if(res == 0)
	{
		printf("yes\n");
	}
}