#include <iostream>
#include <vector>
using namespace std;
 
 
unsigned long long  powerOf(unsigned long long a, unsigned long long b)
{
    unsigned long long temp = a;
 
    for(unsigned long long i = 1; i < b; ++i)
    {
        temp *= a;
    }
 
    return temp;
}
 
int getLeastSignificantDigit(unsigned long long a, unsigned long long b)
{
    if(b == 0)
        return 1;
 
    int m = b % 4;
    if(m == 1)
        return a % 10;
    else if(m == 2 || m == 3)
        return powerOf(a, m) % 10;
    else //(m == 0)
        return powerOf(a, 4) % 10;
}
 
int main()
{
    int tc = 0;
    unsigned long long a = 0, b = 0;
    cin >> tc;
    vector<int> results;
    while(tc--)
    {
        cin >> a >> b;
        results.push_back(getLeastSignificantDigit(a, b));
    }
 
    for(unsigned long long i = 0; i < results.size(); ++i)
    {
        cout << results[i]
             << endl;
    }
 
    return 0;
}

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