c1, c2, c3, c4 = map(int, input().split())

# Compute the numerator for the discriminant's formula
term1 = (c4 * c1 - c3 * c2) ** 2
term2 = 4 * (c3 ** 2 - c4 * c2) * (c1 * c3 - c2 ** 2)
numerator = term1 + term2

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