import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


c1,c2,c3,c4 = MI()
X1 = (c1*c4-c2*c3)/(c1*c3-c2**2)
X2 = (c2*c4-c3**2)/(c1*c3-c2**2)
D = X1**2-4*X2
print('I' if D < 0 else 'R')