#include<iostream>
#include<string>
#include <vector>
#include<queue>
#include<map>
#include<algorithm>
#include<iomanip>
#include<cmath>
#include<bitset>
using namespace std;
using vi = vector<int>;
using vii = vector<vi>;
using vs = vector<string>;
using pii = pair<int, int>;
#define rep(i,n) for(int i=0;i<n;i++)
#define rep2(i,m,n) for(int i=m;i<n;i++)
#define vsort(v) sort(v.begin(), v.end())
#define rv(v) reverse(v.begin(), v.end())
#define ll long long
using vll = vector<ll>;
using Graph = vii;
const ll MOD = 1e9 + 7;

int main() {
	string s;
	cin >> s;
	bool b = true;
	int n = s.size();
	rep(i, n + 1) {
		if (i % 2 == 0) {
			if (s[i] == ' ') {
				b = false;
				break;
			}
		}
		else {
			if (s[i] != ' ') {
				b = false;
				break;
			}
		}
	}

	if (b) cout << "Yes" << endl;
	else cout << "No" << endl;
}