#include <iostream>
#include <fstream>
#include <math.h>
#include <string.h>
#include <stdlib.h>
using namespace std;
ifstream f("cifra.in");
ofstream g("cifra.out");
int T,V[]={0,1,5,2,8,3,9,2,8,7},lg;
long S,cat;
char Numar[105];

int main()
{
     f>>T;
     for(int i=1;i<=T;i++)
     {
         f.get(); f.get(Numar,105);
         lg=strlen(Numar); S=0;
         if(atoi(&Numar[lg-2])%2==0) S+=atoi(&Numar[lg-2]);
         else S+=atoi(&Numar[lg-2])+6;
         S+=V[atoi(&Numar[lg-1])];
         g<<S%10<<'\n';
     }
    return 0;
}