A = raw_input()
B = raw_input()
try :
    int(A)
    int(B)
except ValueError :
    print "NG"
    exit()

if A.lstrip("0") != A or B.lstrip("0") != B :
    print "NG"
    exit()

if int(A)>12345 or int(B)>12345:
    print("NG")
    exit()
print("OK")