#include <bits/stdc++.h>

using namespace std;

ifstream fin("koba.in");
ofstream fout("koba.out");
const int mod = 10;
int n, i, _t, t1, t2, t3, r;

int main() {
    fin >> n >> t3 >> t2 >> t1;

    t1 %= mod;
    t2 %= mod;
    t3 %= mod;
    r = t1 + t2 + t3;

    for(i = 4; i <= n; i++) {
        _t = (t1 + t2 * t3 % mod) % mod;
        r += _t;

        t3 = t2;
        t2 = t1;
        t1 = _t;
    }
    fout << r;

    return 0;
}