import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

A,B = read().split()

def is_ok(A):
    if not A.isdigit():
        return False
    if len(A) > 1 and A[0] == ord('0'):
        return False
    A = int(A)
    return 0 <= A <= 12345

answer = 'OK' if is_ok(A) and is_ok(B) else 'NG'
print(answer)