// yukicoder 328 (http://yukicoder.me/problems/703)
#include<iostream>
#define rep(i,a) for(int i=0;i<(a);++i)

int c[4];

int main()
{
	rep( i, 4 )
		std::cin >> c[i];

	double det = c[0]*c[2]-c[1]*c[1], Z1 = (c[0]*c[3]-c[1]*c[2])/det, Z2 = (c[1]*c[3]-c[2]*c[2])/det;

	puts( Z1*Z1-4*Z2 > 0 ? "R" : "I" );

	return 0;
}