#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

int main() {
	string A, B;
	cin >> A >> B;
	bool ok = true;
	auto func = [](string s) {
		for (char c : s) if (!isdigit(c)) return false;
		if (s.size() > 1 && s[0] == '0') return false;
		int num = stoi(s);
		return num <= 12345;
	};
	ok &= func(A);
	ok &= func(B);
	puts(ok ? "OK" : "NG");
}