#include <bits/stdc++.h>
#define int long long 
using namespace std;


signed main() {
  string S;
  getline(cin, S);
  for( int i = 0; i < S.size(); i++ ){
    if( i % 2 == 0 && S.at(i) == ' ' ){
      cout << "No" << endl;
      return 0;
    }else if( i % 2 == 1 && S.at(i) != ' ' ){
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
  
}