import java.util.*; import java.math.*; public class No446 { public static void main(String[] args) { // 標準入力から読み込む際に、Scannerオブジェクトを使う。 Scanner sc = new Scanner(System.in); String a = sc.next(), b = sc.next(); String atemp = a.replaceAll("\\D", ""); String btemp = b.replaceAll("\\D", ""); if(a.length() == atemp.length() && b.length() == btemp.length() && a.charAt(0) != '0' && b.charAt(0) != '0') { int ai = Integer.parseInt(atemp); int bi = Integer.parseInt(btemp); if(ai <= 12345 && bi <= 12345) { System.out.println("OK"); }else { System.out.println("NG"); } }else { System.out.println("NG"); } } }