#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;
using ll = long long;
using ld = long double;

#define all(x)  x.begin(),x.end()
#define v(x) vector<x>
#define nl '\n'
#define fxd(x) fixed << setprecision(x)
template<class t> using ordered_set = tree<t, null_type, less<t>, rb_tree_tag, tree_order_statistics_node_update>;
template<class t> using ordered_multiset = tree<t, null_type, less_equal<t>, rb_tree_tag, tree_order_statistics_node_update>;


ll fastpower(ll a , ll b ,ll m)
{
    ll ret = 1;
    while (b > 0)
    {
        if(b&1) ret = ((ret%m) * (a%m))%m;
        a = ((a%m) * (a%m))%m;
        b /= 2; 
    }
    return ret;
}


int main()
{
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
    int n ; cin >> n;
    while (n--)
    {
        ll a , b; cin >> a >> b;
        cout << fastpower(a,b,10) << nl; 
    }
    
}