#include <fstream>
#include <cstring>
using namespace std;
ifstream f("cifra.in");
ofstream g("cifra.out");
int n,i,j,p,sum=0,val[105],t;
char a[500];
int main()
{
    for (n=1;n<100;n++)
    {
        sum=0;
        for (i=1;i<=n;i++)
    {
        p=1;
        for (j=1;j<=i;j++)
        {
            p=(p*i)%10;
        }
        sum=(sum+p)%10;
    }
    val[n]=sum;
    }
    f>>t;
    for (i=1;i<=t;i++)
    {
        f>>a;
        if (strlen(a)==1)
        {
            g<<val[a[0]-'0']<<'\n';
        }
        else
        {
            g<<val[a[0]-'0'+(a[1]-'0')*10]<<'\n';
        }
    }
    return 0;
}