#include <fstream>

using namespace std;
ifstream fin("cifra.in");
ofstream fout("cifra.out");

int cifra ( char c)
{
	return c -'0';
}

int main()
{
	char s;
	int t, u[] = {4, 1, 5, 2, 8, 3, 9,2, 8, 7, 7, 8, 4, 7, 3, 8, 4, 1, 5, 4};

	fin>>t;
	fin.get();
	while( t )
	{
		fin.get(s);
		int x = cifra(s), r = 0;

		fin.get(s);
		while( '0' <= s && s <= '9' && !fin.eof() )
		{
			x = x * 10 + cifra(s);
			r = 4*(x/20);
			x %= 20 ;
			fin.get(s);
		}
		t--;
		r = ( r + u[x] ) % 10;
		fout << r << '\n';
	}

	fin.close();
	fout.close();
	return 0;
}