#include <iostream>
using namespace std;
int main(){
    string a,b;cin>>a>>b;
    int A = 0;
    for(int i = 0; a.size() > i; i++){
        if(a == "0")break;
        if(!i){
            if(!('0' < a[i] && a[i] <= '9')){
                cout <<"NG" << endl;
                return 0;
            }
        }else{
            if(!('0' < a[i] && a[i] <= '9')){
                cout <<"NG" << endl;
                return 0;
            }
        }
        A = A*10+a[i]-'0';
    }
    int B = 0;
    for(int i = 0; b.size() > i; i++){
        if(b == "0")break;
        if(!i){
            if(!('0' < b[i] && b[i] <= '9')){
                cout <<"NG" << endl;
                return 0;
            }
        }else{
            if(!('0' < b[i] && b[i] <= '9')){
                cout <<"NG" << endl;
                return 0;
            }
        }
        B = B*10+b[i]-'0';
    }
    if(A <= 12345 && B <= 12345){
        cout << "OK" << endl;
    }else{
        cout << "NG" << endl;
    }
}