#include<iostream>
using namespace std;
long c1,c2,c3,c4;
main()
{
	cin>>c1>>c2>>c3>>c4;
	long X=c1*c3-c2*c2;
	long al=c2*c4-c3*c3;
	long be=c1*c4-c2*c3;
	cout<<(be*be<4*al*X?"I":"R")<<endl;
}