A=input()
B=input()
if A.isdigit()==True and B.isdigit()==True and int(A)<=12345 and int(B)<=12345:
    if str(A[0])!="0" and str(B[0])!="0" or len(A)==1 or len(B)==1:
        print("OK")
else:
    print("NG")