#include <iostream>
#include <cstdlib>
using namespace std;

int digit(int n){
	int cnt=0;
	if(n==0) return 1;
	while(n%10!=0){
		cnt++;
		n/=10;
	}
	return cnt;
}

int main(){
	int flaga=0,flagb=0;
	string a,b;
	cin>>a>>b;
	int aa=atoi(a.data());
	int bb=atoi(b.data());
	if(a.size()!=digit(aa)||b.size()!=digit(bb)){
		cout<<"NG"<<endl;
	}else if(aa>=0&&aa<=12345&&bb>=0&&bb<=12345){
		cout<<"OK"<<endl;
	}else{
		cout<<"NG"<<endl;
	}
	return 0;
}