#include <bits/stdc++.h>
using namespace std;
const long long INF = 1000000000000000;
int main(){
  int N, K;
  cin >> N >> K;
  vector<int> A(N);
  for (int i = 0; i < N; i++){
    cin >> A[i];
  }
  if (K <= N - K){
    long long ans1 = 0, ans2 = 0;
    for (int i = 0; i < K; i++){
      ans1 += A[i] - A[0];
      ans2 += A[N - 1] - A[N - 1 - i];
    }
    for (int i = K; i < N; i++){
      ans1 -= A[i] - A[0];
      ans2 -= A[N - 1] - A[N - 1 - i];
    }
    cout << min(ans1, ans2) << endl;
  } else {
    assert(false);
  }
}