#include <iostream>
using namespace std;
int main ()
{
	char znak;
	int a;
	cin >> znak;
	switch(znak)
	{
		case '0':
		cout << "0";
		break;
		case '1':
		cout << "1";
		break;
		case '2':
		cout << "2";
		break;
		case '3':
		cout << "3";
		break;
		case '4':
		cout << "4";
		break;
		case '5':
		cout << "10";
		break;
		case '6':
		cout << "11";
		break;
		case '7':
		cout << "12";
		break;
		case '8':
		cout << "13";
		break;
		case '9':
		cout << "14";
		break;
		case 'a':
		cin >> a;
		cout << "15";
		break;
	}
	return 0;
}