#include <iostream>
 
using namespace std;
 
int main()
{
    int a;
    int b;
    int D;
    cin>>D;
    int wynik=1;
    while(D>0)
    {
        D--;
        cin>>a>>b;
        a=a%10;
        if(a==0||a==1||a==5||a==6)
            wynik=a;
        else
        for(int i=1; i<=b; i++)
        {
            wynik*=a;
            if(i==5)
            {
                wynik=a;
            }
 
        }
        cout<<wynik%10<<endl;
        wynik=1;
    }
    return 0;
 
}
 

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