#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  string S;
  getline(cin, S);
  for(int i=0;i<S.size();i++){
      if((i%2 == 0 && S[i] == ' ')||(i%2 == 1 && S[i] != ' ')){
          cout<<"No"<<endl;
          return 0;
      }
  }
  cout<<"Yes"<<endl;
}