a = input()
b = input()

if not (a[0] == '0' and len(a) > 1) and not (b[0] == '0' and len(b) > 1) \
    and a.isdigit() and b.isdigit() \
    and (0<int(a) and int(a)<12345) and (0<int(b) and int(b)<12345):
    print('OK')
else:
    print('NG')