#include <string>
#include <iostream>
using namespace std;
int main() {
	string str;
	getline(cin, str);
	bool ok = true;
	for (int i = 0; i < str.size(); ++i) {
		if (str[i] == ' ' && i % 2 == 0) ok = false;
		if (str[i] != ' ' && i % 2 == 1) ok = false;
	}
	cout << (ok ? "Yes" : "No") << endl;
	return 0;
}