Asteroid belt

Many people think the Prienai Way asteroid belt is full of asteroids. Lukas has a map that shows the empty parts of the belt. On the map, the belt is divided into $M \times N$ squares, and each square is either empty or full of asteroids.

Lukas wants to fly through the asteroid field. He can only fly through empty squares.

Lukas's spaceship can fly horizontally for as long as needed. Flying vertically uses fuel: 1 fuel unit for each square passed vertically. Lukas's destination is a planet in square $(X_2, Y_2)$.

Find the smallest amount of fuel Lukas needs to reach the destination.

The first line contains the length $M$ and the height $N$ of the asteroid field.

The second line contains Lukas's starting coordinates $X_1$, $Y_1$ and the destination coordinates $X_2$, $Y_2$.

The third line contains a single integer $K$, the number of empty regions.

Each of the next $K$ lines contains three natural numbers $h_i$, $a_i$, $b_i$. This means that in row $h_i$, squares $a_i$ through $b_i$ inclusive are empty.

Both the starting point and the destination belong to one of the $K$ empty regions. No two empty regions in the same row touch or overlap.

Print one integer, the smallest amount of fuel needed to reach the destination. If the destination cannot be reached, print $-1$.

$1 \le X_1, X_2 \le M$

$1 \le Y_1, Y_2 \le N$, $1 \le a_i \le b_i \le M$

$1 \le h_i \le N$.