#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int ultcif(int x)
{
int t,i;
t=x%10;
for (i=1;i<x;i++)
  t=(t*(x%10))%10;
return t;
}

int main()
{
FILE *f,*f1;
char n[100];
int t,i,j,l,s[100];

for (i=1;i<101;i++)
  {
  s[i-1]=0;
  for (j=1;j<=i;j++)
    s[i-1]=(s[i-1]+ultcif(j))%10;
  }


f1=fopen("cifra.out","w");
  f=fopen("cifra.in","r");
  fscanf(f,"%d",&t);
  for(i=0;i<t;i++)
    {
      fscanf(f,"%s",n);
      l=strlen(n);
      if (l>1)
	fprintf(f1,"%d\n",s[(n[l-2]-'0')*10+n[l-1]-'0'-1]);
      else
	fprintf(f1,"%d\n",s[n[0]-'0'-1]);

    }
  fclose(f);
fclose(f1);



return 0;
}