#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


# %%
*C, = map(int, read().split())

# %%
p = C[0] * C[2] - C[1] ** 2
q = C[1] * C[3] - C[2] ** 2
r = C[0] * C[3] - C[1] * C[2]

# %%
mult = q / p
add = r / p
D = add**2 - 4 * mult

# %%
print('R' if D >= 0 else 'I')