import math
import sys
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int, sys.stdin.readline().rstrip().split())
def LI(): return list(map(int, sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

a = S()
b = S()

if a.isdigit() and b.isdigit() and (len(a) == 1 or a[0] != '0') and (len(b) == 1 or b[0] != '0') and 0 <= int(a) <= 12345 and 0 <= int(b) <= 12345:
    print("OK")
else:
    print("NG")