#include <fstream>

using namespace std;

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

int n, a, b, c, d;
long long sum;

int main()
{
    fin>>n>>a>>b>>c;
    a %= 10; b %= 10; c %= 10;
    for(int i = 1; i <= n; i++){
        sum += a;
        d = a * b  + c;
        d %= 10;
        a = b;
        b = c;
        c = d;
    }
    fout<<sum;
    return 0;
}