#include<iostream>
#include<string>
#include<cstdlib>
template<typename T>
void fin(T const& t){ std::cout << t << std::endl; exit(0); }

int main() {
  std::string S; std::cin >> S;
  S[1] = 'R'+'B' - S[1];
  fin(S);
  return 0;
}
