E2

#include <bits/stdc++.h>

using namespace std;


#define _test   int _TEST; cin>>_TEST; while(_TEST--)

int main()
{
    _test
    {
        auto ask = [](int x)
        {
            cout<<"? "<<x<<endl;
            int tmp;
            cin>>tmp;
            return tmp;
        };

        int n, k;
        cin>>n>>k;

        int XOR = 0;

        int i;
        for(i=1; i+k-1<=n; i+=k)
            XOR ^= ask(i);

        if(i > n)
        {
            cout<<"! "<<XOR<<endl;
            continue;
        }

        int x = ask(n-k+1 - (n%k)/2);
        int y = ask(n-k+1);
        XOR ^= (x^y);

        cout<<"! "<<XOR<<endl;
    }
}