#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <fstream>
#include <sstream>
#include<set>
#include<stack>
#include<time.h>
#include <sys/types.h>
#include <tuple>
#include <numeric>


typedef long long int ll;
//#include<bits/stdc++.h>


using namespace std;







int main()
{

    int Q;
    Q = 1;
    //cin >> Q;

    while (Q--) {
        string s;
        bool f = 1;
        getline(cin, s);
        stringstream ss(s);
        while (getline(ss, s, ' '))
        {
            if (s.size() >= 2) {
                f = 0;
            }
        }
        if (f)cout << "Yes";
        else cout << "No";
                                     
    }
    return 0;
}