Inventory Management
Output: Standard Output (stdout)
Memory limit: 128 megabytes
Time limit: 0.5 seconds
Leon is a preparing to fight an invasion of zombies in a village. However, it is too dangerous to fight zombies unarmed, and Leon has run out of ammunition for his handgun.
Fortunately, the local merchant has N knives on sale, each of which has a particular durability rating. The ith knife is durable enough to kill d_i zombies.
Leon has enough money to buy all of them, but his briefcase only has enough space to hold K knives.
What is the maximum number of zombies Leon can kill if he packs his briefcase optimally?
Input
The first line contains two spaceseparated integers, N, the number of knives on sale, and K, the maximum number of knives Leon can hold.
The second line contains N spaceseparated integers, d_1, d_2, \dots, d_N, the durability ratings of each knife.
Output
You should print a single integer – the maximum number of zombies Leon can kill.
Constraints
 1 \le K \le N \le 100\,000
 1 \le d_i \le 100
Subtasks
 Subtask 1 (30%): K = 1
 Subtask 2 (30%): N \le 1000
 Subtask 3 (40%): No further restrictions apply

Sample Input 1
3 1 4 7 5
Sample Output 1
7

Sample Input 2
5 3 5 3 9 6 7
Sample Output 2
22