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()
{
  char a[27];
  int i, j, n, flag=0;
  //入力
  scanf("%s", &a);
  n = strlen(a);
  //処理
  for(i=0; i<n; i++)
  {
    for(j=0; j<n; j++)
    {
      if(a[i] == a[j] && i != j)
      {
        flag = 1;
      }
    }
  }
  //出力
  if(flag == 0)
  {
    printf("yes\n");
  }
  else
  {
    printf("no\n");
  }
  return 0;
}