#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,a,b) for(it i=(it)(a);i<=(it)b;i++)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define moda 998244353LL
#define modb 1000000007LL
#define dai 2500000000000000000LL
#define tyu 2500000000
#define sho -dai
#define eps 1e-14
#define yn(x) cout<<(x ? "Yes":"No")<<endl;
#define YN(x) cout<<(x ? "YES":"NO")<<endl;
using it=long long;
using un=unsigned long long;
using db=long double;
using st=string;
using ch=char;
using bo=bool;
using P=pair<it,it>;
using T=tuple<it,it,it>;
using vi=vector<it>;
using vd=vector<db>;
using vs=vector<st>;
using vc=vector<ch>;
using vb=vector<bo>;
using vp=vector<P>;
using sp=set<P>;
using ss=set<st>;
using si=set<it>;
using vvi=vector<vi>;
using vvd=vector<vd>;
using vvs=vector<vs>;
using vvb=vector<vb>;
using vvc=vector<vc>;
using vvp=vector<vp>;
using vsi=vector<si>;
using vsp=vector<sp>;
using vvsi=vector<vsi>;
using vvsp=vector<vsp>;
using vvvi=vector<vvi>;
using vvvd=vector<vvd>;
using vvvvi=vector<vvvi>;
using mint=modint;
const it dx[4]={0,1,0,-1};
const it dy[4]={1,0,-1,0};

it itmodo(st a){
  it b=0;
  for(ch c:a){
    b*=10;
    b+=c-'0';
  }
  return b;
}

bo engyes(st a){
  for(ch c:a){
    if(!(c>='0'&&c<='9'))return true;
  }
  return false;
}

bo zero(st a){
  return a[0]=='0'&&a.size()>1;
}

int main(){
  st a,b;cin>>a>>b;
  if(engyes(a)||engyes(b))cout<<"NG\n";
  else if(itmodo(a)>12345||itmodo(b)>12345)cout<<"NG\n";
  else if(zero(a)||zero(b))cout<<"NG\n";
  else cout<<"OK\n";
}