#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 10000000000000000



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