### BUGGY CODE ###

# #!/usr/bin/env python
# from __future__ import division, print_function

# import os
# import sys
# from io import BytesIO, IOBase

# if sys.version_info[0] < 3:
#     from __builtin__ import xrange as range
#     from future_builtins import ascii, filter, hex, map, oct, zip

# from math import sqrt, floor, factorial, gcd
# from collections import deque, Counter, defaultdict


# # region fastio

# BUFSIZE = 8192


# class FastIO(IOBase):
#     newlines = 0

#     def __init__(self, file):
#         self._fd = file.fileno()
#         self.buffer = BytesIO()
#         self.writable = "x" in file.mode or "r" not in file.mode
#         self.write = self.buffer.write if self.writable else None

#     def read(self):
#         while True:
#             b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
#             if not b:
#                 break
#             ptr = self.buffer.tell()
#             self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
#         self.newlines = 0
#         return self.buffer.read()

#     def readline(self):
#         while self.newlines == 0:
#             b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
#             self.newlines = b.count(b"\n") + (not b)
#             ptr = self.buffer.tell()
#             self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
#         self.newlines -= 1
#         return self.buffer.readline()

#     def flush(self):
#         if self.writable:
#             os.write(self._fd, self.buffer.getvalue())
#             self.buffer.truncate(0), self.buffer.seek(0)


# class IOWrapper(IOBase):
#     def __init__(self, file):
#         self.buffer = FastIO(file)
#         self.flush = self.buffer.flush
#         self.writable = self.buffer.writable
#         self.write = lambda s: self.buffer.write(s.encode("ascii"))
#         self.read = lambda: self.buffer.read().decode("ascii")
#         self.readline = lambda: self.buffer.readline().decode("ascii")


# def print(*args, **kwargs):
#     """Prints the values to a stream, or to sys.stdout by default."""
#     sep, file = kwargs.pop("sep", " "), kwargs.pop("file", sys.stdout)
#     at_start = True
#     for x in args:
#         if not at_start:
#             file.write(sep)
#         file.write(str(x))
#         at_start = False
#     file.write(kwargs.pop("end", "\n"))
#     if kwargs.pop("flush", False):
#         file.flush()


# if sys.version_info[0] < 3:
#     sys.stdin, sys.stdout = FastIO(sys.stdin), FastIO(sys.stdout)
# else:
#     sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)

# input = lambda: sys.stdin.readline().rstrip("\r\n")
# read = lambda: list(map(int, input().split(" ")))
# endregion

import sys
inp = sys.stdin.readline
read = lambda: list(map(int, inp().strip().split()))


def solve():
    n, k =read(); arr = read()
    dp = [10**9 for i in range(n)]; dp[0] = 0
    for i in range(n):
    	for j in range(1, k+1):
    		if i-j >-1:
    			dp[i] = min(dp[i], dp[i-j]+abs(arr[i-j] - arr[i]))
    # print(dp)
    print(dp[-1])

    

if __name__ == "__main__":
	solve()

### FIXED CODE ###

import sys
# import numpy as np
inp = sys.stdin.readline
read = lambda: list(map(int, inp().strip().split()))
# import profile

def solve():
    n, k =read(); arr = read()
    dp = [-1]*n; dp[0] = 0
    for i in range(n):
    	for j in range(1, k+1):
    		if i-j >-1:
    			tem = dp[i-j]+abs(arr[i-j] - arr[i])
    			if dp[i] == -1:
    				dp[i] = tem
    			elif dp[i] > tem:
    				dp[i] = tem
    				# dp[i] = min(dp[i], tem)
    print(dp[-1])

def one():
	l = [0]*10**7
def two():
	l = [0 for i in range(10**7)]

if __name__ == "__main__":
	solve()
	# cProfile.run(solve())
	# profile.run(one())
	# cProfile.run()