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