#include <bits/stdc++.h>
#define INF 990000000
//9
using namespace std;

int main() {

string s;
cin>>s;
int flag=0;
for(int i=0;i<(int)s.size();i++){
if(i%2==0){
if(!islower(s[i]))flag=1;
}else{
if(s[i]!=' ')flag=1;
}

}
if(flag==0)
cout << "Yes"<<endl;
else
cout << "No"<<endl;


}