#include <bits/stdc++.h>
#include <iostream>
#include <string>
#include <vector>

using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
typedef long long ll;

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