import sys
input=sys.stdin.readline
def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))
mod=10**9+7

def main():
    N,K=MI()
    A=LI()
    A.sort(reverse=True)
    ans=A[0]
    for i in range(1,min(N,K)):
        temp=ans+A[i]
        if temp>ans:
            ans=temp
        else:
            break
    print(ans)
    


main()