#include <iostream>
#include <fstream>

using namespace std;

ifstream fin ("koba.in");
ofstream fout ("koba.out");

unsigned long long n, a[10], sm;
short int aux, nr;

int main()
{
fin >> n >> a[1] >> a[2] >> a[3];
a[1] = a[1] % 10;
a[2] = a[2] % 10;
a[3] = a[3] % 10;
nr = 1;

for (int i = 1; i <= n; i ++)
{
    a[4] = (a[3] + a[2] * a[1]) % 10;

    a[1] = a[2];
    a[2] = a[3];
    a[3] = a[4];

    sm += a[4];

    nr ++;
    if (nr == 4) nr = 1;
}

fout << sm;

return 0;
}