13 test

a = int(input())
b = int(input())
c = int(input())
h = 0
n = 0
if a + b <= c or a + c <= b or b + c <= a\
        or a <= 0 or b <= 0 or c <= 0:
    n = 1
    print('impossible')
if a < b:
    a, b = b, a
    if a < c:
        a, c = c, a
if n != 1 and a ** 2 == (b ** 2 + c ** 2):
    print('rectangular')
elif n != 1 and a ** 2 > (b ** 2 + c ** 2) or a == b == c:
    print('acute')
elif n != 1 and a ** 2 < (b ** 2 + c ** 2):
    print('obtuse')