#include<fstream.h>
int main ()
{
	ifstream fcin("cifra.in");
	FILE *f=fopen("cifra.in","r");
	ofstream fcout("cifra.out");
	int i,j,uc,x,z,s=0,t,a,c[21]={0,1,4,7,6,5,6,3,6,9,0,1,6,3,6,5,6,7,4,9,0};
	char y;
	fscanf(f,"%d",&t);fscanf(f,"%c",&y);
	uc=4;
	for(i=1;i<=t;i++)
		{x=0;y=-2;z=x;uc=4;s=0;
		 while(y!='\n')
		 {fscanf(f,"%c",&y);
		 if(y!='\n')
		 {z=x;x=y-48;}}
		 uc=(uc*(z/2))%10;
		 a=z%2*10+x;
		 for(j=1;j<=a;j++)
			 s=s+c[j];
		 uc=(uc+s)%10;
		 fcout<<uc<<'\n';}
		return 0;
}