#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;

typedef long long ll;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(c) string(1,c)
#define print(x) cout<<#x<<" = "<<x<<endl;

#define MOD 1000000007

long long ston(string s){
  long long n;
  sscanf(s.c_str(), "%lld", &n);
  return n;
}

int f(string s){
	int flag = 1;
	if(s.sz!=1&&s[0]=='0'){
		flag = 0;
	}
	rep(i,0,s.sz){
		if(s[i]>='0'&&s[i]<='9'){

		}
		else{
			flag = 0;
		}
	}
	ll n = ston(s);
	if(0<=n&&n<=12345){

	}
	else{
		flag = 0;
	}
	return flag;
}

int main() {
	string a,b;
	cin>>a>>b;
	if(f(a)==1&&f(b)==1){
		cout << "OK" << endl;
	}
	else{
		cout << "NG" << endl;
	}
	return 0;
}