#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

//#include<bits/stdc++.h>



using namespace std;




int main() {
	
	
	string a,b;
	cin>>a>>b;
	int x=0,y=0;
	for(int i=0;i<a.size();i++){
		if(a[i]>='0'&&a[i]<='9'){
			if(x==0&&a[i]=='0'&&a.size()>1){
				cout<<"NG"<<endl;
				return 0;
			}
			x*=10;x+=a[i]-'0';

		}
		else{
				cout<<"NG"<<endl;
				return 0;
			}
	}

	for(int i=0;i<b.size();i++){
		if(b[i]>='0'&&b[i]<='9'){
			if(y==0&&b[i]=='0'&&b.size()>1){
				cout<<"NG"<<endl;
				return 0;
			}
			y*=10;y+=b[i]-'0';

		}
		else{
				cout<<"NG"<<endl;
				return 0;
			}
	}
	if(x<=12345&&y<=12345)cout<<"OK"<<endl;
	else cout<<"NG"<<endl;

	return 0;
}