#include <iostream>
#include <vector>
using namespace std;

int main(){
  double c1,c2,c3,c4,delt;
  double plu,mult;
  
  cin >> c1 >> c2 >> c3 >> c4;

  delt = c1*c3-c2*c2;
  plu = (-c2*c3+c1*c4)/delt;
  mult = (-c3*c3+c2*c4)/delt;

  delt = plu*plu-4*mult;

  (delt<0)?(cout<<"I"):(cout<<"R");
  cout << endl;
}