#include <fstream>
#include <cstring>
   
int main() {
	char const * const inputFile = "cifra.in",
											 * const outputFile = "cifra.out";
	std::ifstream in(inputFile);
	std::ofstream out(outputFile);
	
	const int partialSum[] = {
    0, 1, 5, 2, 8, 3, 9, 2, 8, 7, 7, 8, 4, 7, 3, 8, 4, 1, 5, 4
  };
	 
	char buffer[128];
	in >> buffer;
	while (in >> buffer) {
			int size = strlen(buffer), n = buffer[size - 1] - '0';
			if (size > 1)
				n += 10 * (buffer[size - 2] - '0');
			out << ((partialSum[n % 20] + 4 * (n / 20)) % 10) << std::endl;
		}
	return 0;
}