#include <bits/stdc++.h>
using namespace std;
long long sum(long long first) { return first * (first - 1) / 2; }
long long S(long long l, long long r) {
  long long Q = sum(r - l + 1);
  return Q + (r - l + 1) * l;
}
long long get_pos(long long block, long long k) {
  if (block == 1) return S(1, k) - 1;
  long long where = (block - 1) / k + 1, pos = (block - 1) % k;
  long long L = (k * k + 1) * (where - 1) + k * pos + 1,
            R = (k * k + 1) * (where - 1) + k * (pos + 1);
  long long T = get_pos(where, k) + (k * k + 1) * (where - 1) + 1;
  long long sum = S(L, R);
  if (T < L) {
    sum -= L;
    sum += (R + 1);
  } else if (T <= R) {
    sum -= T;
    sum += (R + 1);
  }
  return sum - ((block - 1) * (k * k + 1) + 1);
}
void solve() {
  long long n, k;
  cin >> n >> k;
  long long block = (n - 1) / (k * k + 1) + 1, pos = (n - 1) % (k * k + 1);
  long long spec = get_pos(block, k);
  if (spec == pos) {
    cout << block * (k + 1) << "\n";
    return;
  }
  long long gp = k * k * (block - 1) + pos - (pos > spec);
  cout << gp + gp / k + 1 << "\n";
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t;
  cin >> t;
  for (long long i = 0; i < t; ++i) solve();
}
