لغز للمبرمجين (كم عدد $ لكل عنصر) ؟

for (int r = 1 ; r <= 4 ; r++)

        for (int y = 2 ; y <= 5 ; y++)
            for (int x = 3 ; x <= 6 ; x++)
                for (int z = 4 ; z <= 7 ; z++)
                    if (r < y && y < x && x < z && x + y == z && z + r == 7)
                        System.out.println("x  = " + x  + ", y = " + y + ", r = " + r + ", z = "+ z);

output:x = 4, y = 2, r = 1, z = 6