#include <bits/stdc++.h>
#include <iostream>
#include <string>
#include <vector>

using namespace std;
#define rep(i,n) for(int i=1;i<n;i++)
typedef long long ll;

int main(){
  string s;
  cin >> s;
  rep(i,s.size()){
    if(s[2*i]==' '||s[2*i+1]!=' '){
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
}