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

#define FOR(i, m, n) for(int (i) = (m); (i) < (n); (i)++)
#define REP(i, n) FOR(i, 0, n)
#define co(n) cout << (n) << endl
#define cosp(n) cout << (n) << ' '
#define all(s) (s).begin(), (s).end()
#define pb push_back
#define mp make_pair
#define fs first
#define sc second
typedef long long ll;
typedef pair<int, int> P;

const ll INF = 2e9;
const ll MOD = 1e9+7;
//const ll MOD 998244353;

int main(void){
	char str[200];
	fgets(str, 105, stdin);

	int len = strlen(str);
	REP(i, len-1){
		if(!(i%2)){
			if(str[i] >= 'a' && str[i] <= 'z') continue;
		}else{
			if(str[i] == ' ') continue;
		}
		co("No");
		return 0;
	}

	co("Yes");

	return 0;
}