import sys



from numba import njit, void, i8

input = sys.stdin.buffer.readline

K = int(eval(input()))

A, B = list(map(int, input().split()))





@njit(i8(i8, i8, i8), cache=True)

def main(K, A, B):



    for i in range(A, B + 1):

        if i % K == 0:

            print('OK')

            return 0

    print('NG')

    return 0





if __name__ == '__main__':

    main(K, A, B)

import sys



from numba import njit, b1, i8





@njit(b1(i8, i8, i8), cache=True)

def solve(K, A, B):

    for i in range(A, B + 1):

        if i % K == 0:

            return True

    return False





def main():

    input = sys.stdin.buffer.readline

    K = int(eval(input()))

    A, B = list(map(int, input().split()))



    print(('OK' if solve(K, A, B) else 'NG'))





if __name__ == '__main__':

    main()

import sys
from numba import njit, void, i8

input = sys.stdin.buffer.readline
K = int(eval(input()))
A, B = list(map(int, input().split()))


@njit(i8(i8, i8, i8), cache=True)
def main(K, A, B):
    for i in range(A, B + 1):
        if i % K == 0:
            print("OK")
            return 0
    print("NG")
    return 0


if __name__ == "__main__":
    main(K, A, B)

import sys
from numba import njit, b1, i8


@njit(b1(i8, i8, i8), cache=True)
def solve(K, A, B):
    for i in range(A, B + 1):
        if i % K == 0:
            return True
    return False


def main():
    input = sys.stdin.buffer.readline
    K = int(eval(input()))
    A, B = list(map(int, input().split()))
    print(("OK" if solve(K, A, B) else "NG"))


if __name__ == "__main__":
    main()

-from numba import njit, void, i8 - -input = sys.stdin.buffer.readline -K = int(eval(input())) -A, B = list(map(int, input().split())) +from numba import njit, b1, i8 -@njit(i8(i8, i8, i8), cache=True) -def main(K, A, B): +@njit(b1(i8, i8, i8), cache=True) +def solve(K, A, B): -            print("OK") -            return 0 -    print("NG") -    return 0 +            return True +    return False + + +def main(): +    input = sys.stdin.buffer.readline +    K = int(eval(input())) +    A, B = list(map(int, input().split())) +    print(("OK" if solve(K, A, B) else "NG")) -    main(K, A, B) +    main()