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: Accepted)

#include"stdio.h"
#include"string.h"
main(){
	char S[26];
	int i,j;
	gets(S);
	for(i=0;i<(strlen(S)-1);i++)
	{for(j=i+1;j<strlen(S);j++)
	{if(S[i]==S[j]) break;}
	if(j!=strlen(S)) break;}
	if(i==(strlen(S)-1)) printf("yes\n");
	else printf("no\n");
}