#include <iostream>
#include<string>
#include<sstream>
using namespace std;

int main() {
	string a,b;
	cin>>a>>b;
	bool flag=true;
	if((a[0]=='0'&&a!="0")||(b[0]=='0'&&b!="0"))flag=false;
	for(int i=0;i<a.size();i++)
	{
		if(a[i]<'0'||a[i]>'9')flag=false;
	}
	for(int i=0;i<b.size();i++)
	{
		if(b[i]<'0'||b[i]>'9')flag=false;
	}
	stringstream s1,s2;
	int ss1,ss2;
	s1<<a;
	s1>>ss1;
	s2<<b;
	s2>>ss2;
	if(ss1>12345||ss2>12345)flag=false;
	if(flag)cout<<"OK"<<endl;
	else cout<<"NG"<<endl;
	return 0;
}