#include<fstream>   
#include<cstring>   
 using namespace std;  
 int main(){   
   int sol[]={0,1,5,2,8,3,9,2,8,7,7,8,4,7,3,8,4,1,5,4,4};//solutiile calculate   
   int i, t,lungime,nr,suma=0;   
   char s[101];   
   ifstream f("cifra.in");   
   ofstream g("cifra.out");   
   f>>t;   
   f.get();   
   for(i=0;i<t;i++)
   {   
     f.getline(s,102);   
     lungime=strlen(s);   
     if(lungime>1)
     {   
       nr=s[lungime-1]-'0'+((s[lungime-2]-'0')%2)*10;   
       suma=sol[nr];   
       nr=(s[lungime-2]-'0');   
       nr-=nr%2;   
       nr/=2;   
       suma=suma+(nr*sol[20])%10;   
       g<<suma%10<<'\n';   
     }   
     else g<<sol[s[0]-'0']<<'\n';   
   }   
   f.close();   
   g.close();   
   return 0;   
 }