#include <iostream>
#include <algorithm>

using namespace std;

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