#include <fstream>

using namespace std;

int main()
{
    ifstream in("ucif.in");
    ofstream out("ucif.out");
    int uc,n,i,s=0,j,k,p;
    in>>n;
    for(i=1;i<=n;i++){
        p=1;
        k=i%4;
        if(k==0)
            k=4;
            for(j=1;j<=k;j++)
                p=p*i%10;
        s+=p;
    }
    out<<s%10;
    return 0;
}