#include<bits/stdc++.h>
using namespace std;

bool suuji(string str){
	bool num = true;
	for(int i = 0; i < str.length(); i++){
		if(str[i] - '0' >= 0 && str[i] - '0' <= 9){
			if(str.length() == 1 && str[i] - '0' == 0){
				break;
			}else if(i == 0 && str[i] - '0' == 0){
				num = false;
				break;
			}
		}else{
			num = false;
			break;
		}
	}
	return num;
}

int StringToInt(string str){
  stringstream ss;
  ss << str;
  int num;
  ss >> num;
  return num;
}

int main(){
	string a, b;
	cin >> a >> b;
	if(suuji(a) == true && suuji(b) == true){
		int n = StringToInt(a);
		int m = StringToInt(b);
		if(n >= 0 && n <= 12345 && m >= 0 && m <= 12345){
			cout << "OK" << endl;
		}else{
			cout << "NG" << endl;
		}
	}else{
		cout << "NG" << endl;
	}
}