#define _GLIBCXX_DEBUG
#define ll long long
#define INF 1000000000;
#define INF_B 1000000000000000000;
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int main(){
  string A, B; cin >> A >> B;
  if((int)A.size() != 1 and A[0] == '0'){
    cout << "NG" << endl;
    return 0;
  }
  int a = 0;
  for(int i = 0; i < (int)A.size(); i++){
    if(!('0' <= A[i] and A[i] <= '9')){
      cout << "NG" << endl;
      return 0;
    }
    a *= 10;
    a += A[i] - '0';
  }
  if((int)B.size() != 1 and B[0] == '0'){
    cout << "NG" << endl;
    return 0;
  }
  int b = 0;
  for(int i = 0; i < (int)B.size(); i++){
    if(!('0' <= B[i] and B[i] <= '9')){
      cout << "NG" << endl;
      return 0;
    }
    b *= 10;
    b += B[i] - '0';
  }
  if(a > 12345 or b > 12345){
    cout << "NG" << endl;
    return 0;
  }
  cout << "OK" << endl;
}