#include <iostream>
using namespace std;
int a,b,c,proba;
int main()
{
cin>>proba;
while(proba--)
{cin>>a;
cin>>b;
c=a;
for(int i=1;i<b;i++)
{
c=c*a;
}
c=c%10;
cout<<c<<endl;
}
return 0;
}
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