import re
a = input()
b = input()

if (re.match(r'^([1-9][0-9]*|0)$', a) is None) or \
   (re.match(r'^([1-9][0-9]*|0)$', b) is None):
    print("NG")
else:
    a = int(a)
    b = int(b)
    if 0 <= a <= 12345 and 0 <= b <= 12345:
        print("OK")
    else:
        print("NG")