#coding: UTF-8

import sys
import re
import itertools
from collections import deque

""" defs """

""" main """
c1, c2, c3, c4 = map(int,input().split())
x = c1*c3 - c2*c2
y = c2*c4 - c3*c3
z = c1*c4 - c2*c3

d = (z*z - 4*x*y)/(x*x)

if (d >= 0):
	print ("R")
else:
	print ("I")