#include <iostream>
#include <fstream>

using namespace std;

ifstream f("cifra.in");
ofstream g("cifra.out");

int t;

int Suma(int n)
{int s=0;
 int v2[4]={2,4,8,6};
 int v3[4]={3,9,7,1};
     for(int i=1;i<=n;i++)
     switch(i%10)
     {
          case 0:s+=0;
          case 1:{s+=i%10; break;}
          case 2:{s+=v2[(i-1)%4]; break;}
          case 3:{s+=v3[(i-1)%4]; break;}
          case 4:{if(i%2==1) s+=4; else s+=6; break;}
          case 5:{s+=5; break;}
          case 6:{s+=6; break;}
          case 7:{s+=v3[(i+1)%4]; break;}
          case 8:{s+=v2[(i+1)%4]; break;}
          case 9:{if(i%2==1) s+=9; else s+=1; break;}
     }
     return s%10;
}

void Citire()
{
     char x;
     int i=0;
     f>>t;
     while(i!=t)
     {
          i++;
          f>>x;
          int l=x-'0';
          g<<Suma(l)<<endl;

     }
}


int main()
{Citire();

    return 0;
}