#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  string s;
  getline(cin, s);

  bool ck = true;
  REP (i, s.length()) {
    if (i % 2 == 0)
      ck &= s[i] != ' ';
    else
      ck &= s[i] == ' ';
  }
  if (ck)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  
  return 0;
}