CF797F.Mice and Holes

One day Masha came home and noticed n mice in the corridor of her flat. Of course, she shouted loudly, so scared mice started to run to the holes in the corridor.

The corridor can be represeted as a numeric axis with n mice and m holes on it. _i_th mouse is at the coordinate x__i, and _j_th hole — at coordinate p__j. _j_th hole has enough room for c__j mice, so not more than c__j mice can enter this hole.

What is the minimum sum of distances that mice have to go through so that they all can hide in the holes? If _i_th mouse goes to the hole j, then its distance is |x__i - p__j|.

Print the minimum sum of distances.

一天，玛莎回到家，发现公寓走廊里有 n 只老鼠。当然，她大声喊叫，受惊的老鼠们立刻开始朝走廊里的洞穴奔逃。

走廊可建模为一条数轴，其上有 n 只老鼠和 m 个洞穴。第 i 只老鼠位于坐标 x__i 处，第 j 个洞穴位于坐标 p__j 处。第 j 个洞穴最多可容纳 c__j 只老鼠，即至多 c__j 只老鼠能进入该洞穴。

所有老鼠全部躲进洞穴所需经过的最小总距离是多少？若第 i 只老鼠进入第 j 个洞穴，则它所走的距离为 |x__i - p__j|。

请输出该最小总距离。

The first line contains two integer numbers n, m (1 ≤ n, m ≤ 5000) — the number of mice and the number of holes, respectively.

The second line contains n integers _x_1, _x_2, ..., x__n ( - 109 ≤ x__i ≤ 109), where x__i is the coordinate of _i_th mouse.

Next m lines contain pairs of integer numbers p__j, c__j ( - 109 ≤ p__j ≤ 109, 1 ≤ c__j ≤ 5000), where p__j is the coordinate of _j_th hole, and c__j is the maximum number of mice that can hide in the hole j.

第一行包含两个整数 $n$、$m$（$1 \leq n, m \leq 5000$），分别表示老鼠的数量和洞穴的数量。

第二行包含 $n$ 个整数 $x_1,\ x_2,\ \dots,\ x_n$（$-10^9 \leq x_i \leq 10^9$），其中 $x_i$ 表示第 $i$ 只老鼠的坐标。

接下来的 $m$ 行每行包含一对整数 $p_j,\ c_j$（$-10^9 \leq p_j \leq 10^9$，$1 \leq c_j \leq 5000$），其中 $p_j$ 表示第 $j$ 个洞穴的坐标，$c_j$ 表示第 $j$ 个洞穴最多能容纳的老鼠数量。

Print one integer number — the minimum sum of distances. If there is no solution, print -1 instead.

输出一个整数——距离之和的最小值。若无解，则输出 -1。