Green plantings

Input

The first line contains the number of planted areas, $N$ ( $1 \leq N \leq 100$ 1 \leq N \leq 100). Each of the following $N$ lines contains $4$ integers, separated by spaces, representing the coordinates of the opposite corners of each rectangular area.

$X_{1}$ X_1, $Y_{1}$ Y_1, $X_{2}$ X_2, $Y_{2}$ Y_2 ( $∣ X_{1} ∣, ∣ Y_{1} ∣, ∣ X_{2} ∣, ∣ Y_{2} ∣ \leq 2000$ |X_1|, |Y_1|, |X_2|, |Y_2| \leq 2000)

Output

Output a single number: the total perimeter of the green plantings.

Examples

Example 1

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