import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const N = readInt;
      const K = N - readInt;
      auto A = new long[N];
      foreach (i; 0 .. N) {
        A[i] = readLong;
      }
      
      auto ASum = new long[N + 1];
      foreach (i; 0 .. N) {
        ASum[i + 1] = ASum[i] + A[i];
      }
      
      long ans = long.max;
      const half = N / 2;
      foreach (k; 0 .. K + 1) {
        const l = max(k - 1, 0);
        const r = min(N - (K - k), N - 1);
        // (-1) k, (+1) N-K, K-k
        // K-k, N-K, k
        const im = (half < K - k) ? l : (half < N - k) ? (k + (half - (K - k))) : r;
        long calc(int i0, int i1) {
          long ret;
          if (i0 <= im) {
            // \sum (A[im] - A[i])
            const lb = i0;
            const ub = min(i1, im);
            ret += A[im] * (ub - lb);
            ret -= (ASum[ub] - ASum[lb]);
          }
          if (im < i1) {
            // \sum (A[i] - A[im])
            const lb = max(i0, im);
            const ub = i1;
            ret += (ASum[ub] - ASum[lb]);
            ret -= A[im] * (ub - lb);
          }
          debug {
            writefln("  calc %s %s %s = %s", im, i0, i1, ret);
          }
          return ret;
        }
        long cost;
        cost -= calc(0, k);
        cost += calc(k, N - (K - k));
        cost -= calc(N - (K - k), N);
        debug {
          writefln("%s: %s %s; %s; %s", k, l, r, im, cost);
        }
        chmin(ans, cost);
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}