# coding: utf-8

import sys



sr = lambda: sys.stdin.readline().rstrip()

ir = lambda: int(sr())

lr = lambda: list(map(int, sr().split()))



K = ir()

A, B = lr()

left = -(-A//K)

right = B // K

bl = left <= right

if A % K == 0 or B % K == 0:

    bl = True

print(('OK' if bl else 'NG'))

# coding: utf-8

import sys



sr = lambda: sys.stdin.readline().rstrip()

ir = lambda: int(sr())

lr = lambda: list(map(int, sr().split()))



K = ir()

A, B = lr()

left = -(-A//K)

right = B // K

bl = left <= right

print(('OK' if bl else 'NG'))

# coding: utf-8
import sys

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))
K = ir()
A, B = lr()
left = -(-A // K)
right = B // K
bl = left <= right
if A % K == 0 or B % K == 0:
    bl = True
print(("OK" if bl else "NG"))

# coding: utf-8
import sys

sr = lambda: sys.stdin.readline().rstrip()
ir = lambda: int(sr())
lr = lambda: list(map(int, sr().split()))
K = ir()
A, B = lr()
left = -(-A // K)
right = B // K
bl = left <= right
print(("OK" if bl else "NG"))

-if A % K == 0 or B % K == 0: -    bl = True