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 Python (3.4.3) (judge verdict: Wrong Answer)

#n = int(input())
#n,k = map(int,input().split())
#x = list(map(int,input().split()))




#62
s = list(input().split())
jg = {}

for i in range(len(s)):
    if s[i] in jg:
        print("no")
        break
    else:
        jg[s[i]] = 1
    
    if i == len(s):
        print("yes")