#include <iostream>

using namespace std;

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

    bool ret = true;
    for (int i = 0; i < s.size(); i++) {
        if ((i % 2 == 1) != (s[i] == ' ')) ret = false;
    }

    cout << (ret ? "Yes" : "No") << endl;
    return 0;
}