#include <bits/stdc++.h>
using namespace std;
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
const long long MOD = 1e9 + 7;
const long long INF = 1e9 + 8;
const double pi = 3.14159265359;
long long binpow(long long a, long long b, long long m) {
  a %= m;
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a % m;
    a = a * a % m;
    b >>= 1;
  }
  return res;
}
long long inverse(long long x) { return binpow(x, MOD - 2, MOD); }
void solve() {
  long long n, x;
  cin >> n >> x;
  if (n <= 2) {
    cout << 1 << endl;
    return;
  }
  cout << (n - 3) / x + 2 << endl;
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  long long t;
  cin >> t;
  while (t--) solve();
  cerr << "Time elapsed : " << 1.0 * clock() / CLOCKS_PER_SEC << " sec \n ";
}
