#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define repr(i, n) for (int i = (n) - 1; i >= 0; i--)
#define rep2(i, l, r) for (int i = (l); i < (r); i++)
#define rep2r(i, l, r) for (int i = (r) - 1; i >= (l); i--)
#define range(a) a.begin(), a.end()

using namespace std;
using ll = long long;

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  string s;
  getline(cin, s);
  rep(i, s.size()) {
    if (i % 2 == 0 && s[i] == ' ') {
      cout << "No" << endl;
      return 0;
    }
    if (i % 2 == 1 && s[i] != ' ') {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
}