One more line

A coordinate plane has $2n+2$ lines drawn on it. The lines are $x = 0, x = 1, \cdots, x = n$ and $y = 0, y = 1, \cdots, y = n$. Bsil was counting the rectangles that can be formed from this figure.

Then a segment connecting the points $(x_a + 0.5, y_a + 0.5)$ and $(x_b + 0.5, y_b + 0.5)$ was added. Bsil, who likes solving every problem with a single formula, now faces a very hard problem. To help him, count the rectangles with sides parallel to the coordinate axes whose sides can be formed from the intersections of lines with lines or lines with the segment.

The first line contains an integer $n$. ($1 \le n \le 10^4$)

The second line contains two integers $x_a$ and $y_a$. ($-10^4 \le x_a, y_a \le 10^4$)

The third line contains two integers $x_b$ and $y_b$. ($-10^4 \le x_b, y_b \le 10^4$)

It is guaranteed that $(x_a + 0.5, y_a + 0.5)$ and $(x_b + 0.5, y_b + 0.5)$ are different points.

Print the answer to the problem.