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>

int main(void){
  char s[27];
  int t[27]={0};
  int n, i=0;

  scanf("%s", s);
  n=strlen(s);

  while(s[i]!='\0'){
    t[s[i]-'a']++;
    i++;
  }

  for(i=0;i<n;i++){
    if(t[i]>=2){
    puts("no");
    break;
  }
    if(i==n-1)
    puts("yes");
  }
    return 0;
  }