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>
  char f[100];
  int w[1000];
int main()
{
  int i,j,k,l,m,n,num,p;
  scanf("%s",f);m=0;
  l=strlen(f); for (i=0;i<l;i++)
    w[f[i]]++;
  for (i=50;i<200;i++)
   if (w[i]>1)m=1;
  if (m==1)printf("no");
  else printf("yes");

  return 0;
}