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: Accepted)

//kalyanchirla
//#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <climits>
#include <utility>
#include <algorithm>
#include <cmath>
#include <queue>
#include <stack>
#include <iomanip>
//setbase - cout << setbase (16)a; cout << 100 << endl; Prints 64
//setfill -   cout << setfill ('x') << setw (5); cout << 77 <<endl;prints xxx77
//setprecision - cout << setprecision (14) << f << endl; Prints x.xxxx
//cout.precision(x)  cout<<fixed<<val;  // prints x digits after decimal in val
using namespace std;
#define int long long
#define f(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) f(i,0,n)
#define csl ios_base::sync_with_stdio(false);cin.tie(NULL)
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define vi vector<int>
#define mii map<int,int>
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define mod 1000000007

int32_t main()
{ 
    csl;

    string s;
    cin >> s;

    int freq[26];
    for(int i=0;i<26;i++)
    {
        freq[i]=0;
    }
    for(int i=0;i<s.length();i++)
    {
        int a = s[i]-97;
        if(freq[a]==0)
        {
            freq[a]++;
        }
        else
        {
            cout << "no" << "\n";
            return 0;
        }
    }
    cout<< "yes" << "\n";
}