#include <bits/stdc++.h>

using namespace std;

int main() {
  string S;
  getline(cin, S);
  bool check = true;
  for(int i = 0; i < S.size(); i++) {
    if(i & 1) {
      if(S[i] != ' ') check = false;
    } else {
      if(S[i] == ' ') check = false;
    }
  }
  if(check) cout << "Yes" << endl;
  else cout << "No" << endl;
}