Problem:
Score : 200 points

Problem Statement

Snuke has N sticks.
The length of the i-th stick is l_i.

Snuke is making a snake toy by joining K of the sticks together.

The length of the toy is represented by the sum of the individual sticks that compose it.
Find the maximum possible length of the toy.

Constraints

1 \leq K \leq N \leq 50

1 \leq l_i \leq 50

l_i is an integer.

Input

Input is given from Standard Input in the following format:

N K
l_1 l_2 l_3 ... l_{N}

Output

Print the answer.

Sample Input 1

5 3
1 2 3 4 5

Sample Output 1

12

You can make a toy of length 12 by joining the sticks of lengths 3, 4 and 5, which is the maximum possible length.

Sample Input 2

15 14
50 26 27 21 41 7 42 35 7 5 5 36 39 1 45

Sample Output 2

386

Solution in C (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

/* AtCoder Regular Contest 078. Problem B, by Abreto<m@abreto.net>. */
#include <stdio.h>

int K,N;
int l[64];
int sum[64];
int maxsum;

void dfs(int pos, int rem, int cur)
{
    if(0 == rem)
    {
        if(cur > maxsum) maxsum = cur;
    } else {
        int i = 0;
        for(i = pos;i < N-rem+1;++i)
            if( cur + l[i] + sum[N-1] - sum[i] > maxsum )
                dfs(i+1, rem-1, cur+l[i]);
    }
}

int main(void)
{
    int i = 0;

    scanf("%d%d", &N, &K);
    for(i = 0;i < N;++i)
        scanf("%d", l+i);
    sum[0] = l[0];
    for(i = 1;i < N;++i)
        sum[i] = sum[i-1]+l[i];
    dfs(0, K, 0);
    printf("%d\n", maxsum);

    return 0;
}