#include <iostream>
using namespace std;
int main () {
int D;
unsigned long long a, b, w;
cin >> D;
for (int i=1; i<=D; i++)
{
cin >> a >> b;
if (1 <= a,b <= 1000000000)
{
a = a % 10;
w = a;
for (int j=1; j<=b-1; j++)
{
w = w * a;
if (w>=10)
w = w % 10;
}
}
cout << w << endl;
}
}
I2luY2x1ZGUgPGlvc3RyZWFtPgp1c2luZyBuYW1lc3BhY2Ugc3RkOwppbnQgbWFpbiAoKSB7CglpbnQgRDsKCXVuc2lnbmVkIGxvbmcgbG9uZyBhLCBiLCB3OwoJY2luID4+IEQ7Cglmb3IgKGludCBpPTE7IGk8PUQ7IGkrKykKCXsKCQljaW4gPj4gYSA+PiBiOwoJCWlmICgxIDw9IGEsYiA8PSAxMDAwMDAwMDAwKQoJCXsKCQkJYSA9IGEgJSAxMDsKCQkJdyA9IGE7CgkJCWZvciAoaW50IGo9MTsgajw9Yi0xOyBqKyspCgkJCXsKCQkJCXcgPSB3ICogYTsKCQkJCWlmICh3Pj0xMCkKCQkJCXcgPSB3ICUgMTA7CgkJCX0KCQl9CgkJY291dCA8PCB3IDw8IGVuZGw7Cgl9Cn0=