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

// http://www.wolframalpha.com/input/?i=solve[+c1%3Dp1%2Bp2%2C++c2%3Dp1*z1%2Bp2*z2%2C++c3%3Dp1*z1^2%2Bp2z2^2%2C++c4%3Dp1*z1^3%2Bp2*z2^3]

long long pow_(long long x, long long y){
	if(x==0) return 0;
	long long ret = 1;
	while(y){
		if(y&1) ret *= x;
		x *= x;
		y >>= 1;
	}
	return ret;
}

int main(){
	vector<long long> c(4);
	for(auto& v: c) cin >> v;
	long long a = pow_(c[0],2) * pow_(c[3],2) - 6*c[0]*c[1]*c[2]*c[3] + 4*c[0]*pow_(c[2],3) + 4*pow_(c[1],3)*c[3] - 3*pow_(c[1],2)*pow_(c[2],2);
	if(a>0){
		puts("R");
		return 0;
	}
	a = c[0]*c[2] - pow_(c[1],2);
	if(a>0){
		puts("R");
		return 0;
	}
	puts("I");
	return 0;
}