#include <iostream>
#include<math.h>
using namespace std;
int main()
{
int ile;
cin>>ile;
for(int i=0; i<ile; i++)
{
int a,b;
cin>>a>>b;
if(1 <= a,b <= 1000000000)
{
int c= a%10;
int d =b%10;
if(c == 0) c=10;
if(d == 0) d=10;
int e= pow(c,d);
cout<<e%10<<endl;
};
}
return 0;
}
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