#include <iostream>
using namespace std;
int main(){
    string a,b;cin>>a>>b;
    int A = stoi(a);
    int B = stoi(b);
    if(to_string(A) == a && to_string(B) == b && A <= 12345 && B <= 12345){
        cout << "OK" << endl;
    }else{
        cout << "NG"  << endl;
    }
}