a = input()
b = input()

def judge(a, b):
  if a.isdigit() and b.isdigit():
    if str(int(a)) == a and str(int(b)) == b:
      if int(a) <= 12345 and int(b) <= 12345:
        return 'OK'
  
  return 'NG'

print(judge(a, b))