#include <algorithm>
#include <iostream>
#include <tuple>
#include <vector>
using namespace std;
int main() {
vector<std::string> answer;
int a, b, c, k;
cin >> a >> b >> c >> k;
if ((b-c)%(k+3) != 0) {
cout << "NO" << endl;
return 0;
}
cout << "YES" << endl;
while (b + c > 0) {
if (b == c || a == 0) {
--b; --c;
a += (k+2);
answer.push_back("B R");
} else if (b > c) {
--a; --b;
c += (k+2);
answer.push_back("O B");
} else if (c > b) {
--a; --c;
b += (k+2);
answer.push_back("O R");
}
}
cout << answer.size() << endl;
for(auto s: answer) {
cout << s << endl;
}
return 0;
}
