from sys import stdin

def main():

    #入力

    readline=stdin.readline

    K=int(readline())

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

    if A%K==0:

        print("OK")

    elif A//K<B//K:

        print("OK")

    else:

        print("NG")

if __name__=="__main__":

    main()
k=int(input())

a,b=map(int,input().split())

print("OK") if a<=b//k*k else print("NG")

from sys import stdin


def main():
    # 入力
    readline = stdin.readline
    K = int(readline())
    A, B = list(map(int, readline().split()))
    if A % K == 0:
        print("OK")
    elif A // K < B // K:
        print("OK")
    else:
        print("NG")


if __name__ == "__main__":
    main()

k = int(input())
a, b = map(int, input().split())
print("OK") if a <= b // k * k else print("NG")

-from sys import stdin - - -def main(): -    # 入力 -    readline = stdin.readline -    K = int(readline()) -    A, B = list(map(int, readline().split())) -    if A % K == 0: -        print("OK") -    elif A // K < B // K: -        print("OK") -    else: -        print("NG") - - -if __name__ == "__main__": -    main() +k = int(input()) +a, b = map(int, input().split()) +print("OK") if a <= b // k * k else print("NG")