Windows#2397
On the Windows desktop, there are open windows. For each window, the coordinates of its upper-left corner x_i, y_i, as well as its width w_i and height h_i (i = 1..N) are given. Determine how many windows are visible on the screen. A window is considered visible if it is not completely covered by other windows opened after it.
The first line contains the number — the number of windows.
Each of the next lines contains four integers: x_i, y_i, w_i, h_i (i = 1..N). The order of opening the windows corresponds to their order in the input.
All values are positive integers and do not exceed .
Print a single integer — the number of visible windows on the screen.
Example 1