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>
#include <string.h>
int main(int argc, char *argv[])
{
	char a[30];
	int i,j,flag=0;
	scanf("%s",a);
	for(i=0;i<strlen(a);i++)
	{
		for(j=i+1;j<strlen(a);j++)
		{
			if(a[i]==a[j])
			flag=1;
			break;
			
		}
	}
	if(flag==1)printf("no\n");
	else printf("yes\n");
	return 0;
}