#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

int main()
{
	int x,bin;
	cin >> x;
	do
	{
		bin = 0;
		for(int i = 0; i < 4; i++)
		{
			bin += (x & 0x01)*pow(2,i);
			x = x >> 1;
		}
		cout << uppercase << hex << bin;
	}while(x);
	cout << endl;
	return 0;

}