var n = readLine()!.split(separator: " ").map{Int($0)!}
var a = readLine()!.split(separator: " ").map{Int($0)!}.sorted(by: >)
var b = a.removeFirst()
for i in 0...n[1] - 2{
    if a[i] < 0{
        break
    }else{
        b += a[i]
    }
}
print(b)