#include <iostream>

using namespace std;

int main()
{
	int a,b,c,d,x,y;

	cin >> a;
	cin >> b;
	cin >> c;
	cin >> d;

	if(a<=d)
	{
		if(b>=c)
		{
			if(a<c)
			{
				x = c;
			}
			else
			{
				x = a;
			}
			if(d<b)
			{
				y = d;
			}
			else
			{
				y = b;
			}
			cout << "[" << x << "," << y << "]" << endl;
			return 0;
		}
	}
	cout << "[]" << endl;
	return 0;
}