#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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