Demining

Input

The first line contains two positive integers $n$ and m~(1 \le n, m \le 1000) — the number of rows and columns, respectively.

The next $n$ lines contain $m$ integers x_{ij}~(0 \le x_{ij} \le 10^9) — the number of mines in the corresponding sector.

The next line contains an integer k~(1 \le k \le 1000) — the number of pictures taken by the quadcopter.

The next $k$ lines contain the coordinates of the rectangular pictures. Each line contains four integers: y_1, y_2, x_1, and x_2, where:

• y_1 is the row number where the picture starts;

• y_2 is the row number where the picture ends;

• x_1 is the column number where the picture starts;

• x_2 is the column number where the picture ends.

Output

Print one integer — the total number of mines captured in the pictures. Mines that are included in several pictures must be counted only once.

Examples