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>
main()
{
	char s[25];
	int i,j,b=-1;
	do
	{
	scanf("%s",&s);	
	}while(strlen(s)<2||strlen(s)>26);
   for(i=0;i<=strlen(s);i++)
      for(j=1;j<=strlen(s);j++)
       {
		  if(s[i]==s[j])
     	  b=b;
     	  if(s[i]!=s[j])
     	  b=-b;
     	 }
	if(b==1)
	printf("no");
	if(b==-1)
	printf("yes");
		  		
}