#include <bits/stdc++.h>
using namespace std;
#define lli long long int
lli powmod(lli base, lli exp, lli mod)
{
    lli result = 1;
    while (exp > 0)
    {
        if (exp % 2 == 1)
            result = (result * base) % mod;
        exp = exp >> 1;
        base = (base * base) % mod;
    }
    return result;
}
int main() {
	// your code goes here
	int t;
	scanf("%d",&t);
	while(t--)
	{
		lli a,b;
		cin >> a >> b;
		cout<<powmod(a,b,10)<<endl;
	}
	return 0;
}

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