#include<iostream>
#include<fstream>
using namespace std;
int main()
{
    long long n;
    int t[100000000],s,i;
    ifstream cin ("koba.in");
    ofstream cout ("koba.out");
    cin>>n>>t[1]>>t[2]>>t[3];
    t[1]=t[1]%10;
    t[2]=t[2]%10;
    t[3]=t[3]%10;
    s=t[1]+t[2]+t[3];
    for(i=4;i<=n;i++)
    {
                     t[i]=t[i-1]+t[i-2]*t[i-3];
                     t[i]=t[i]%10;
                     s=s+t[i];
    }
    cout<<s;
    cin.close();
    cout.close();
}