#include<fstream>
using namespace std;
ifstream fin("koba.in");
ofstream fout("koba.out");
int n,nr,s;
unsigned long long a,b,c;
int main(){
    fin>>n>>a>>b>>c;
    if(n==1){
        fout<<a%10;
        return 0;
    }
    if(n==2){
        fout<<a%10+b%10;
        return 0;
    }
    if(n==3){
        fout<<a%10+b%10+c%10;
        return 0;
    }
    nr=3;
    s=a%10+b%10+c%10;
    if(n>=4){
        while(nr<=n){
            a=c+b*a;
            nr++;
            s+=a%10;
            if(nr==n){
                fout<<s/10*10;
                break;
            }
            b=a+c*b;
            s+=b%10;
            nr++;
            if(nr==n){
                fout<<s/10*10;
                break;
            }
            c=b+a*c;
            nr++;
            s+=c%10;
            if(nr==n){
                fout<<s/10*10;
                break;
            }
        }
    }
    return 0;
}