#include <iostream>
#include <string>
#include <stdexcept>
using namespace std;
int main(void){
    // Here your code !
    string a,b;
    cin >> a >> b;
    bool f = true;

    if(a[0] == '0' && a.size() != 1) f = false;
    if(b[0] == '0' && b.size() != 1) f = false;


    for(int i = 1; i < a.size(); i++){
        if( !(a[i] >= '0' && a[i] <= '9') ){
            f = false;    
        }
    }
    
    for(int i = 1; i < b.size(); i++){
        if( !(b[i] >= '0' && b[i] <= '9') ){
            f = false;
        }
    }
    
    if(f){
        try{
        if(stoi(a) <= 12345 && stoi(b) <= 12345)
        cout << "OK" << endl;
        else
        cout << "NG" << endl;
        }catch(const std::logic_error& e){
            cout << "NG" << endl;
        }
    }
    else cout << "NG" << endl;

}