import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string;

auto rdsp(){return readln.splitter;}
void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;}
void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}
void readA(T)(size_t n,ref T[]t){t=new T[](n);auto r=rdsp;foreach(ref v;t)pick(r,v);}

void main()
{
  int n, k; readV(n, k);
  int[] h; readA(n, h);

  auto dp = new int[](n); dp[] = 10^^9;
  dp[0] = 0;
  foreach (i; 1..n)
    foreach (j; 1..k+1)
      if (i-j >= 0) dp[i] = min(dp[i], dp[i-j] + (h[i]-h[i-j]).abs);

  writeln(dp[$-1]);
}
