#include <bits/stdc++.h>
using namespace std;
#define int long long
#define REP(i,n) for(int i = 0;i < (int)(n);i++)
#define RREP(i,n) for(int i = (int)n-1;i >= 0;i--)
#define FOR(i,s,n) for(int i = s;i < (int)n;i++)
#define RFOR(i,s,n) for(int i = (int)n-1;i >= s;i--)
#define ALL(a) a.begin(),a.end()
template<class T>inline bool CHMAX(T&a,T b){if(a<b){a = b;return true;}return false;}
template<class T>inline bool CHMIN(T&a,T b){if(a>b){a = b;return true;}return false;}
constexpr long long INF = 1e18;



signed main(){
	string s;
	getline(cin,s);
	int ok = 1;
	REP(i,s.size()){
		if(i%2&&s[i]!=' ')ok=0;
		if(i%2==0&&s[i]==' ')ok=0;
	}
	if(ok)cout << "Yes" << endl;
	else cout << "No" << endl;
}