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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<cstdio>/*c++输入输出*/
#include<iostream>/*c++输入输出*/
#include<cmath>//c++数学 函数
#include<algorithm>//c++算法
#include<cstring>//字符串
#include<map>//数组
#include<queue>//队列
#include<stack>//栈
using namespace std;//……
char s[30];
int vis[125];
int main(){
    scanf("%s",s + 1);
    int l = strlen(s + 1);
    for(int i = 1 ; i <= l; i++){
        vis[s[i] - '0']++;
        if(vis[s[i] - '0'] > 1){
            printf("no");
            return 0;
        }
    }
    printf("yes");
}