C = list(map(int, input().split()))
a = C[0] * C[2] - C[1] * C[1]
b = C[0] * C[3] - C[1] * C[2]
c = C[1] * C[3] - C[2] * C[2]
if b * b - 4 * a * c >= 0:
    print("R")
else:
    print("I")