Day85

//A. Floor Number
import java.util.Scanner;
 
public class FloorNumber {
 
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        int t = scanner.nextInt(); // Number of test cases
        for (int i = 0; i < t; i++) {
            int n = scanner.nextInt(); // Apartment number
            int x = scanner.nextInt(); // Apartments per floor (except first)
            
            int floorNumber;
            if (n <= 2) {
                // If apartment is on the first floor
                floorNumber = 1;
            } else {
                // Calculate which floor Petya lives on
                floorNumber = 1 + (n - 3) / x + 1; // Adding one for the first floor
            }
            
            System.out.println(floorNumber);
        }
        
        scanner.close();
    }
}