#include<bits/stdc++.h>
// #include<atcoder/all>

using namespace std;
// using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using P = pair<int,int>;
#define rep(i,n) for(ll i = 0;i < (ll)n;i++)
#define ALL(x) (x).begin(),(x).end()
#define MOD 1000000007



int main(){
  
  ll n,k;
  cin >> n >> k;
  ll r = k,x = n-k,l = 0;
  k = n-k;
  ll d = 0;
  ll res = 1ll << 60;
  vector<ll> a(n);
  rep(i,n)cin >> a[i],d += a[i]-a[0];
  for(ll i = r;i < n;i++)d -= (a[i]-a[0])*2;
  res = d;
  for(ll i = 1;i < n;i++){
    d += (i-2*(k-x))*(a[i]-a[i-1]);
    d -= (n-i-1-2*x)*(a[i]-a[i-1]);
    while(abs(a[i]-a[r]) < abs(a[i]-a[l])){
      d += 2*(abs(a[i]-a[l])-abs(a[i]-a[r]));
      l++;r++;
      l %= n;r %= n;
      x--;
    }
    res = min(res,d);
  }
  cout << res << "\n";
  

  return 0;
}