#include<stdio.h>
FILE *f=fopen("cifra.in","r"),*g=fopen("cifra.out","w");
char c[102];
int a;
void citire()
{
 int i=1,p;
 c[0]='0';
 fscanf(f,"%c",&c[1]);
 while(c[i]!='\n'&&c[i]!=' ')
  {
  fscanf(f,"%c",&c[++i]);
  fflush(f);  }
 p=i-1;
 c[p]=c[p]-48;
 c[p-1]=c[p-1]-48;
 a=c[p-1]*10+c[p];

}

void cifra()
{
 int s=0,k,j;
 for(int i=1;i<=a;i++)
 {
  int j=i%10;
  {
   if(j==0||j==1||j==5||j==6)
    {
     s=s+j;
    }
    else
     if(j==4||j==9)
      {
       k=i;
       k=k%2;
       if(k==0)
	s=s+j*j;
       else
	s=s+j;
     }
    else
    {
     k=i;
     k=k%4;
     if(k==0)   k=4;
     else
     {
      int m=1;
      for(int l=1;l<=k;l++)
      {m=m*j;
       m=m%10;  }
       s=s+m;
      }
    }
    s=s%10;
  }
 }
 fprintf(g,"%d\n",s);

}


int main()
{
 int n;
 fscanf(f,"%d",&n);
 fscanf(f,"\n");

 for(int i=1;i<=n;i++)
  {
   citire();
   cifra();
  }

 return 0;

}