#include <cstring>
#include "stdio.h"
#include "stdlib.h"

int main()
{
	//da-i bicepsi
	FILE *f = fopen("cifra.in","r");
	FILE *g = fopen("cifra.out","w");

	int n=0;
	fscanf(f,"%d",&n);

	int vector[10][10];
	int vect[10][4] = {{0,0,0,0},
	{1,1,1,1},
	{6,2,4,8},
	{1,3,9,7},
	{6,4,6,4},
	{5,5,5,5},
	{6,6,6,6},
	{1,7,9,3},
	{6,8,4,2},
	{1,9,1,9}};

	//construieste vectorul de constante
	int s = 0;
	vector[0][0] = 0;
	for (int i=1;i<100;i++)
	{
		s = (s+vect[i%10][i%4])%10;
		vector[i/10][i%10] = s;
	}

/*	for (int i=0;i<10;i++)
	{
		for (int j=0;j<10;j++)
			fprintf(g,"%d ",vector[i][j]);
		fprintf(g,"\n");
	}*/
	
	char c;
	char c1,c2;
	c1 = '0';
	c2 = getc(f);
	while ((c=getc(f))!=EOF)
	{
		if (c!='\n')
		{
			c1 = c2;
			c2 = c;
		}
		else
		{
			char cc1[1],cc2[1];
			cc1[0] = c1;
			cc2[0] = c2;
			fprintf(g,"%d\n",vector[atoi(cc1)][atoi(cc2)]);

			c1 = '0';
			c2 = '0';
		}
	}
	char cc1[1],cc2[1];
			cc1[0] = c1;
			cc2[0] = c2;
	fprintf(g,"%d\n",vector[atoi(cc1)][atoi(cc2)]);
	
	fclose(f);
	fclose(g);
}