Problem P
Manhattanstíflur

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As you probably already know, the streets in Manhattan all lay north to south or east to west. Let us number the streets that go from north to south $0, 1, \dots , n$ where the $0$ is the street furthest west. Let us also number the streets going east to west $0, 1, \dots , m$ where $0$ is the street furthest north. Then we can denote an intersection by the numbers of the streets that make up the intersection, from $(0, 0)$ to $(n, m)$. We are interested in being able to get from the north-west corner $(0, 0)$ to the south-east corner $(n, m)$ by travelling along the streets. The problem is that often sections of road are closed due to construction work or other problems. Can you answer when such closures close all routes from $(0, 0)$ to $(n, m)$?

Input

The first line of input contains a single positive integer $q$. Next there is a line with two positive integers $n, m$, the number of streets in either direction. Finally there are $q$ lines, each with information about a section of road that gets closed. Each line contains four integers $x_1, y_1, x_2, y_2$ satisfying $0 \leq x_1, x_2 \leq n$ and $0 \leq y_1, y_2 \leq m$. This means that the section of road from the intersection $(x_1, y_1)$ to the intersection $(y_1, y_2)$ is being closed. These intersections are always adjacent to one another.

Output

If query number $i$ closes all routes from $(0, 0)$ to $(n, m)$, print $i$. If it’s still possible to travel from $(0, 0)$ to $(n, m)$ after all queries, print $-1$ instead.

Scoring

4
1 2
0 2 0 1
0 1 1 1
1 0 1 1
0 2 1 2

3

5
3 3
0 0 1 0
0 1 0 2
1 1 1 2
0 2 1 2
2 1 1 1

-1