#include<bits/stdc++.h>
using namespace std;
int main(){
  string a,b;int al=a.length();int bl=b.length();
  if((a[0]=='0'&&al!=1)||(b[0]=='0'&&bl!=1)){cout<<"NG"<<endl;return 0;}
  int n=0;int m=0;
  for(int i=0;i<al;i++){
    if('0'<=a[i]&&a[i]<='9')n+=(a[i]-'0')*pow(10,al-i-1);
    else{cout<<"NG"<<endl;return 0;}
  }
  for(int i=0;i<bl;i++){
    if('0'<=b[i]&&b[i]<='9')m+=(b[i]-'0')*pow(10,bl-i-1);
    else{cout<<"NG"<<endl;return 0;}
  }
  cout<<((n<=12345&&m<=12345)?"OK":"NG")<<endl;
}