#include <bits/stdc++.h>
using namespace std;
int main() {
  int t, n, x;
  cin >> t;
  for (int i = 0; i < t; i++) {
    cin >> n >> x;
    if (n == 1) {
      cout << 1 << endl;
      continue;
    }
    if (n == 2) {
      cout << 1 << endl;
      continue;
    }
    if ((n - 2) % x == 0)
      cout << (n - 2) / x + 1 << endl;
    else
      cout << (n - 2) / x + 2 << endl;
  }
  return 0;
}
