#include <bits/stdc++.h>

using namespace std;
int n;
int suma(int a)
{

    int t = a;
    int s = 0;
      for(int i = 1; i <= t; i++)
    {
        if(i % 10 == 1)
            s = (s + 1) % 10;
        if(i % 10 == 5)
            s = (s + 5) % 10;
        if(i % 10 == 6)
            s = (s + 6) % 10;
        if(i % 10 == 9)
            s = (s + 9) % 10;
             if(i % 10 == 4)
            s = (s + 6) % 10;
         if(i % 10 == 2)
         {
            if(i % 4 == 2)
                s = (s + 4) % 10;
            else
                s = (s + 6) % 10;
         }

             if(i % 10 == 3)
             {
                   if(i % 4 == 1)
                s = (s + 3) % 10;
            else
                s = (s + 7) % 10;
             }

             if(i % 10 == 7)
             {
                 if(i % 4 == 1)
                    s = (s + 7) % 10;
                 else
                    s = (s + 3) % 10;
             }

             if(i % 10 == 8)
             {
                 if(i % 4 == 1)
                    s = (s + 8) % 10;
                 else
                    s = (s + 2) % 10;
             }


    }
if(t == 0)
    return 0;

    return s%10;

}
int main()
{
 ifstream f ("cifra.in");
 ofstream g ("cifra.out");

f >> n;
f.get();
int s = 0, t;
char e[101];
while(n--)
{
 f.getline(e, 101);
  cout << e << endl;
    int r, r1, r2 ;
    if(strlen(e) == 1)
{

    r1 = e[strlen(e) - 1] - '0';
    g << suma(r1) << '\n';
}
else
{r1 = e[strlen(e) - 1] - '0';
    r2 = e[strlen(e) - 2] - '0';
g << suma(r2 * 10 + r1) << '\n';
}


//fout << suma(r2 * 10 + r1) << endl;
}
return 0;
}