#include<bits/stdc++.h>

using namespace std;

int main()
{
  string A, B;
  cin >> A >> B;


  bool flag = false;
  for(char &c : A) {
    if(!isdigit(c)) {
      flag = true;
    }
  }
  for(char &c : B) {
    if(!isdigit(c)) {
      flag = true;
    }
  }
  if(A.size() > 1 && A.front() == '0') flag = true;
  if(B.size() > 1 && B.front() == '0') flag = true;

  if(!flag && stoi(A) <= 12345 && stoi(B) <= 12345) {
    cout << "OK" << endl;
  } else {
    cout << "NG" << endl;
  }
}