Sale

Bob要去参加一次旧电视卖场，一共有n台电视出售，编号为i的电视的价格为$a_i$。有些电视的价格是个负数，Bob最多会买m台电视，问Bob最多能赚到多少钱。 ### 输入： 第一行两个整数$n,m(1\leq m\leq n\leq 100)$,为待出售的电视机的数目和Bob打算买的电视机的数目。第二行有n个整数，整数之间用空格分开，第i个整数$a_i(-1000\leq a_i\leq 1000)$为第i台电视机的价格. ### 输出： 输出只有一个数字，即Bob最多能赚到的钱。 Translated by @sounkix

Once Bob got to a sale of old TV sets. There were $ n $ TV sets at that sale. TV set with index $ i $ costs $ a_{i} $ bellars. Some TV sets have a negative price — their owners are ready to pay Bob if he buys their useless apparatus. Bob can «buy» any TV sets he wants. Though he's very strong, Bob can carry at most $ m $ TV sets, and he has no desire to go to the sale for the second time. Please, help Bob find out the maximum sum of money that he can earn.

The first line contains two space-separated integers $ n $ and $ m $ ( $ 1<=m<=n<=100 $ ) — amount of TV sets at the sale, and amount of TV sets that Bob can carry. The following line contains $ n $ space-separated integers $ a_{i} $ ( $ -1000<=a_{i}<=1000 $ ) — prices of the TV sets.

Output the only number — the maximum sum of money that Bob can earn, given that he can carry at most $ m $ TV sets.

5 3
-6 0 35 -2 4

8

4 2
7 0 0 -7

7