#include <bits/stdc++.h>
using namespace std;

int main()
{
	string S;
	getline( cin, S );


	string ans = "Yes";
	for( int i = 0; i < S.size(); i++ ) {
		if( i % 2 ) {
			if( S[i] != ' ' ) ans = "No";
		}
		else {
			if( islower( S[i] ) == false ) ans = "No";
		}
	}

	cout << ans << endl;
}