#include <fstream>

using namespace std;
ifstream f("cifra.in");
ofstream g("cifra.out");
char n, t, e;
int i, j, p, k, s;
int main()
{
    f.get(n);
    f.get(e);
    i=1;
    while ( i <= n-'0' ) {
        f.get(t);
        f.get(e);
        s=0;
        for(j=1;j<=t-'0';j++){
            p=1;
            for(k=1;k<=j;k++)
                p=(p*j)%10;
            s=(s+p)%10;
        }
        g << s << "\n";
        i++;
    }
    return 0;
}