Pokemon Hunt

Branimirko plays Pokemon Go a lot. He recently decided to organize a Pokemon catching competition. It is held in Ilica street in Zagreb, and his friend Slavko sponsors it. The reward is candy, of course.

Ilica is the longest street in Zagreb. $N$ houses stand on one side of the street, numbered $1$ through $N$. The competition starts at house $K$.

Before the competition Branimirko looked at the map and found $M$ Pokemon. Pokemon $i$ sits at house $A_i$, is worth $B_i$ candy, and can be caught only before $T_i$ seconds have passed since the start. The moment $T_i$ seconds pass it disappears from the map and cannot be caught any more. No two Pokemon sit at the same house.

Branimirko moves to a neighboring house in one second. At the start, that is at second $0$, he stands at house $K$. When he reaches a house at a time smaller than the $T_i$ of the Pokemon there, he catches that Pokemon and it disappears from the map. Catching takes no time. He may walk over a house he has already visited.

Find the largest amount of candy Branimirko can get.

The first line contains the number of houses $N$, the starting house number $K$ and the number of Pokemon $M$ ($1 \le K \le N \le 1000$, $1 \le M \le 100$).

Each of the next $M$ lines contains $A_i$, $B_i$ and $T_i$ of one Pokemon ($1 \le A_i \le N$, $1 \le B_i \le 100$, $1 \le T_i \le 2000$).

The Pokemon are given in increasing order of house number $A_i$.

Print the largest amount of candy Branimirko can get, on one line.

In the first example Branimirko catches the Pokemon at house 3 (5 candy), then the one at house 7 (10 candy), then the one at house 9 (100 candy), for 115 candy in total. He cannot catch the Pokemon at house 1. Walking there from the starting house 5 takes 4 seconds, and that Pokemon disappears the moment 4 seconds pass.