#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1e9 + 7;
const int inf = (1 << 30) - 1;
const ll infll = (1LL << 61) - 1;
#define fast() ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)

string s;

int main()
{
    getline(cin, s);
    for (int i = 1; i < s.size(); i += 2)
    {
        if (s[i] != ' ')
        {
            cout << "No\n";
            return 0;
        }
    }

    for (int i = 0; i < s.size(); i += 2)
    {
        if (s[i] == ' ')
        {
            cout << "No\n";
            return 0;
        }
    }
    cout << "Yes\n";
}