#include <iostream>
#include <stdio.h>
using namespace std;
int main()
{
int d;
scanf("%d", &d);
int tablica[3][d];
for (int i = 0; i < d; i++) {
cin >> tablica[0][i] >> tablica[1][i];
tablica[2][i] = 1;
for (int j = 0; j < tablica[1][i]; j++) tablica[2][i] *= tablica[0][i];
printf("%d" "%s",tablica[2][i] % 10, "\n");
}
}
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