import sys
read=sys.stdin.buffer.read
readline=sys.stdin.buffer.readline
readlines=sys.stdin.buffer.readlines

c1, c2, c3, c4=map(int, readline().split())
if (c1*c4-c2*c3)*(c1*c4-c2*c3)>=4*(c2*c4-c3**2)*(c1*c3-c2**2):
    print('R')
else:
    print('I')