#include <iostream>
using namespace std;
void hoanvi(int &a, int &b)
{
	if (a > b)
	{
		int temp = a;
		a = b;
		b = temp;
	}
}
void ss(int a, int b, int c, int d)
{
	hoanvi(a, b);
	hoanvi(a, c);
	hoanvi(a, d);
	hoanvi(b, c);
	hoanvi(b, d);
	hoanvi(c, d);
	cout << a;
	cout << b;
	cout << c;
	cout << d;
}
int main()
{
	
	int a, b, c, d;
	cout << "Nhap a: ";
	cin >> a;
	cout << "Nhap b: ";
	cin >> b;
	cout << "Nhap b: ";
	cin >> c;
	cout << "Nhap b: ";
	cin >> d;
	ss(a, b, c, d);
}