#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstring>
#include <cstdlib>
#include <cmath>
using namespace std;
using ll = long long;

int main() {
    string s;
    getline(cin, s);
    int n = s.size();

    int b = 1;
    for (int i = 0; i < n; i++) {
        if ((i % 2 != 0) ^ (s[i] == ' ')) b = 0;
    }
    cout << (b ? "Yes" : "No") << endl;

    return 0;
}