#include <iostream>
using namespace std;
int potega(int a, int b);
int main()
{
    int D,c;
    unsigned long int a,b;
    cin >> D;
    for(int i=0;i<D;i++){
        cin >> a >> b;
        int c = b%4;

        if(b>0 && c>0)
            b=c;

       cout << potega(a,b)%10 << endl;

    }

}
int potega(int a, int b){
    if(b==0)
        return 1;
    else
        return a=a*potega(a,--b);
}