#include <iostream>
using namespace std;
int proby;
long int a,b;
long int pot(long int a,long int b)
{
if(b==0) return 1;
else return a*pot(a,b-1);
}
int main()
{
cin>>proby;
while (proby--)
{
cin>>a>>b;
cout<<pot(a,b)%10<<endl;
}
}
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