// yukicoder: No.328 きれいな連立方程式
// 2019.8.2 bal4u

#include <stdio.h>
#include <math.h>

#define EPS 1e-6

int main()
{
	int c1, c2, c3, c4;
	double t, x1, x2;
	
	scanf("%d%d%d%d", &c1, &c2, &c3, &c4);
	t = c2*c2 - c1*c3;
	x1 = (c2*c3 - c1*c4) / t;
	x2 = (c3*c3 - c2*c4) / t;
	t = x1*x1 - 4*x2;
	puts(fabs(t) <= EPS || t >= 0 ? "R": "I");
	return 0;
}