#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <cmath>
#include <map>
#include <queue>
#include <iomanip>
#include <set>
#include <tuple>
#define mkp make_pair
#define mkt make_tuple
#define rep(i,n) for(int i = 0; i < (n); ++i)
using namespace std;
typedef long long ll;
const ll MOD=1e9+7;

int main(){
  string S;
  getline(cin,S);

  bool flag=true;
  for(int i=0;i<S.size();i++){
    if(i%2==0&&S[i]==' ') flag=false;
    if(i%2&&S[i]!=' ') flag=false;
  }

  if(flag) cout<<"Yes"<<endl;
  else cout<<"No"<<endl;

  return 0;
}