#include <iostream>
 
using namespace std;
 
int numberoftests, base, exponent, sum;
 
int main()
{
    cin >> numberoftests;
    for(int i = 0; i < numberoftests; i++)
    {
        cin >> base >> exponent;
        sum = base;
        for(int i = 1; i < exponent; i++)
        {
            if (i == 1) sum = base;
            if(exponent == 1) break;
            sum = sum * base;
        }
        cout << sum % 10 << endl;
    }
    return 0;
}

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