#include <bits/stdc++.h>
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = 1LL << 60;
template <class T>
inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
ll gcd(ll n, ll m) {
  ll tmp;
  while (m != 0) {
    tmp = n % m;
    n = m;
    m = tmp;
  }
  return n;
}
ll lcm(ll n, ll m) { return abs(n) / gcd(n, m) * abs(m); }
using namespace std;
void solve() {
  int t;
  cin >> t;
  while (t--) {
    int n, x;
    cin >> n >> x;
    if (n <= 2) {
      cout << 1 << "\n";
    } else {
      n -= 2;
      cout << (n - 1) / x + 2 << "\n";
    }
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout << fixed << setprecision(15);
  solve();
  return 0;
}
