#include <fstream>
#include <cstring>
using namespace std;

int m0du10(int n)
{
   long long sum_f=1;
   for(int i=1; i<=n; i++)
   {  sum_f*=n;
      sum_f=sum_f%10; }
   return sum_f;
}

int main()
{   ifstream in("cifra.in");
    ofstream out("cifra.out");
    int v[100];
    int t,x;
    char n[10000],c;
    v[0]=0;
    for(int i=1; i<100; ++i)
      v[i]=(v[i-1]+m0du10(i))%10;
    in>>t;
    for(int i=1;i<=t;i++)
    {
        in.get(c);
        in.get(n,10000);
        if(strlen(n)==1)
          x=n[strlen(n)-1]-'0';
        else
          x=(n[strlen(n)-1]-'0') + (n[strlen(n)-2]-'0')*10;
        out<<v[x]<<endl;  }
    in.close();
    out.close();
    return 0;
}