week_2_8(2)

#include <iostream>                                     #include <vector>

using namespace std;

long long fib_number(int n) {                                   vector<long long> f(n+1);                               f[0] = 1;                                               f[1] = 1;
        for (int i = 2; i < n+1; i++) {
                f[i] = f[i-1] + f[i-2];
        }

        long long sum = ( f[n] % 10) *( f[n-1] % 10);

        return sum % 10;                                }

int main() {
        int n;                                                  cin >> n;                                               cout << fib_number(n) << endl;                  }