#include <iostream>

using namespace std;

int main(void)
{
	int i;
	int a[3];

	for(i = 0; i < 3; i++){
		cin >> a[i];
	}
	a[0] = a[0]^2;
	a[1] = a[1]^2;
	a[2] = a[2]^2;

	if((a[0] == (a[1] + a[2])) || (a[1] == (a[0] + a[2])) || (a[2] == (a[0] + a[1]))){
		cout << "OK " << endl;
	}
	else{
		cout << "NG" << endl;
	}
	return 0;
	
}