#include <iostream>
#include <cassert>
using namespace std;

class Fibonacci final {
public:
    static int get_last_digit(int n) {
        assert(n >= 1);
        int a = 0, b = 1;
        int last_digit;
        for (int i = 2; i <= n; i++) {
            last_digit = (a + b) % 10;
            a = b;
            b = last_digit;
        }
        return last_digit;
    }
};

int main(void) {
    int n;
    std::cin >> n;
    std::cout << Fibonacci::get_last_digit(n) << std::endl;
    system("PAUSE");
    return 0;
}