#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(ll i=0;i<n;i++)

int main(){
  string a,b;
  cin>>a>>b;
  int flag=1;
  int lena=a.length();
  int lenb=b.length();
  if(a.at(0)=='0' && lena>1){
    cout<<"NG"<<endl;
    return 0;
  }
  if(b.at(0)=='0' && lenb>1){
    cout<<"NG"<<endl;
    return 0;
  }    
  
  int x=0;
  for(int i=0;i<lena;i++){
    if(a.at(i)>'9' || a.at(i)<'0'){
      cout<<"NG"<<endl;
      return 0;
    }
    x+=(a.at(i)-'0');
    if(i != lena-1){
      x*=10;
    }
  }
  if(x>12345){
    cout<<"NG"<<endl;
    return 0;
  }
  
  x=0;
  for(int i=0;i<lenb;i++){
    if(b.at(i)>'9' || b.at(i)<'0'){
      cout<<"NG"<<endl;
      return 0;
    }
    x+=(b.at(i)-'0');
    if(i != lenb-1){
      x*=10;
    }
  }
  if(x>12345){
    cout<<"NG"<<endl;
    return 0;
  } 
  cout<<"OK"<<endl;
  return 0;
}