import std.stdio, std.string, std.conv;
import std.range, std.algorithm, std.array, std.typecons, std.container;
import std.math, std.numeric, core.bitop;

enum inf = 1L << 50;

void main() {
    int n, k;
    scan(n, k);
    auto h = readln.split.to!(int[]);

    auto dp = new long[](n + 1);

    foreach (i ; 1 .. n) {
        long t = inf;
        foreach (j ; max(0, i - k) .. i) {
            t = min(t, dp[j] + abs(h[i] - h[j]));
        }
        dp[i] = t;
    }

    writeln(dp[n-1]);
}







void scan(T...)(ref T args) {
    import std.stdio : readln;
    import std.algorithm : splitter;
    import std.conv : to;
    import std.range.primitives;

    auto line = readln().splitter();
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}


void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}