#include<bits/stdc++.h>
using namespace std;
using ll = long long;


void solve()
{
    int n,x;
    cin>>n>>x;
    n=n-2;
    int f;
    if(n%x==0) f=n/x+1;
    else f=n/x+2;
    cout<<f<<endl;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int TC = 1;
    cin >> TC;
    cin.ignore();
    while (TC--) solve();
}