mansoura contest #1 H. Triago ###watest2

#include <iostream>
#include <iomanip>
#include <algorithm>
#include <string>
#include <map>
#include <cmath>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
    int t;
    cin >> t;
    while (t--) {
        double n, m;
        cin >> n >> m;
        long long sum = n * (n + 1) / 2;
        //cout << sum << endl;
        long long sub = 0;
        long long i = pow(n, 1 / m);
        //cout << i << endl;
        while (i > -1) {
            sub += pow(m, i);
            //cout << sub << endl;
            i--;
        }
        if (n==1) cout << -1 << endl;
        else if (n<m) cout << sum-2 << endl;
        //cout << sub << endl;
        else
        cout << sum - 2 * sub << endl;
    }
    return 0;
}