#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<algorithm>

using namespace std;

#define int long long
#define endl "\n"

const long long INF = (long long)1e18;
const long long MOD = 1'000'000'007; 

string yn(bool f){return f?"Yes":"No";}
string YN(bool f){return f?"YES":"NO";}



signed main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);
	
	string S;
	bool flag = true;
	
	// cin>>S;
	
	getline(cin,S);
	
	for(int i = 0; i < S.size(); i++){
		if(i%2){
			if(S[i] != ' '){
				flag = false;
			}
		} else {
			if(S[i] == ' '){
				flag = false;
			}
		}
		// cout<<S[i]<<endl;
	}
	
	cout<<yn(flag)<<endl;
	
	return 0;
}