#include<stdio.h>

unsigned int n;

int a[11][5] ={ {0,0,0,0,0},{1,1,1,1,1},{6,2,4,8,6},{1,3,9,7,1},{6,4,6,4,6},
{5,5,5,5,5},{6,6,6,6,6},{1,3,9,7,1},{6,8,4,2,6},{1,9,1,9,1},{0,0,0,0,0} };


unsigned int i,T,k,j,s;
char c,c1,c2,c3,c4;

int main(){

FILE *f=fopen("cifra.in","r");
fscanf(f,"%u\n",&T);
FILE *g=fopen("cifra.out","w");

for(i=1;i<=T;i++){


  while(!feof(f)){
  fscanf(f,"%c",&c3);
  if(c3=='\n'){c=c1;c1=c2;c2=c;break;}
  c1=c3;
  fscanf(f,"%c",&c4);
  if(c4=='\n'){break;}
  c2=c4;


  }


n=(c2-48)*10+(c1-48);
s=0;
k=0;

  for(j=1;j<=n;j++)
  s+=a[j%10][j%4];

fprintf(g,"%u\n",s%10);

}


fclose(g);
fclose(f);
return 0;
}