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 9.2.1) (judge verdict: Wrong Answer)

#include <unistd.h>
 
void ft_putchar(char c)
{
  write(1, &c, 1);
}
 
void ft_putstr(char *str)
{
  while(*str)
    ft_putchar(*(str++));
}
 
int main()
{
  int i;
  int j;
  char c[27];
  
  i = 0;
  while(c[i])
    c[i] = 0;
  read(0, c, 26);
  i = 0;
  while (c[i])
  {
    j = i + 1;
  		while (c[j])
        {
          if (c[i] = c[j])
          {
            ft_putstr("no");
            return 0;
          }
          j++;
        }
    i++;
  }
  ft_putstr("yes");
  return 0;
}