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>
int main(){
  char s[27];
  int a[26]={0},b=0,c=1;
  scanf("%s",s);
  while(s[b]!='\0'){
    a[ s[b]-'a' ]++;
    b++;
  }
  for(int i=0; i<26; i++){
    if(a[i]>1){c=0;break;}
  }
  printf(c?"yes":"no");
  return 0;}