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>
int judgestr(char str[],int len)
{
  int i,n;
  for(n = 0;n<len-1;n++)
    for(i=n+1;i<len;i++)
      if(str[n] - str[i] == 0)
        return 1;
  return 0;
}

int main()
{
  char str[27];
  fgets(str,26,stdin);
  if(str[strlen(str)-1] == '\n')
    str[strlen(str)-1] = '\0';
  if(judgestr(str,strlen(str)) == 0)
    printf("yes\n");
  else
    printf("no\n");
  return 0;
}