//SECOND TEMPLATE

#include <bits/stdc++.h>
using namespace std;
 
#define gcu              getchar unlocked
#define gc              getchar
#define pcu              putchar_unlocked
#define pc              putchar
 
#define pb    		    push_back

#define FOR(i,a,b)      for(ll i=(a);i<=(b);i++)
#define FORD(i,a,b)     for(ll i=(a);i>=(b);i--)
#define ForA(n)  	    for (ll i=0; i<n; i++)
#define ForA2(n)  	    for (ll j=0; j<n; j++)
#define ForA3(n)  	    for (ll k=0; k<n; k++)
#define ForN(n)  	    for (ll i=1; i<=n; i++)
#define ForN2(n)  	    for (ll j=1; j<=n; j++)
#define ForN3(n)  	    for (ll k=1; k<=n; k++)
#define SortA(n,x) 	    sort(n,n+x);
#define SortS(s)  	    sort(s.begin(), s.end());
#define SortRS(s)  	    sort(s.rbegin(), s.rend());
#define Search(s)       s.begin(), s.end()
#define SortSG(n)	    sort(n.begin(), n.end(), greater<int>());
#define Cin(a) 	        cin>>a;
#define GCin(a)	    	getline(cin,a);
#define Sz(a)		    a.size()
#define Cin2(a,b)	    cin>>a>>b;
#define Cin3(a,b,c)	    cin>>a>>b>>c;
#define Cin4(a,b,c,d)   cin>>a>>b>>c>>d;
#define Unique(n)       sort(Search(n)),n.erase(unique(Search(n)),n.end())
#define PI 	            3.1415926535897932384626433832795l
#define Ignore	        cin.ignore();
#define Cout(n)		    cout<<n<<endl;
#define mem(n,i)        memset(n,i,sizeof n);
#define deci(n)         cout<<fixed<<setprecision(n);
#define square(n)       n*n
#define cube(n)         n*n*n
#define F               first
#define S               second
#define bug()		    cerr<<"*****<>*****\n";
 
typedef unsigned long long ull;
typedef long double ldb;
typedef long long ll;
typedef stringstream SS;
typedef vector<string> VS;
typedef vector<ll> VI;
typedef vector<char> VC;
typedef map<string, string> MSS;
typedef map <ll,string> MIS;
typedef map <char,ll> MCI;
typedef map <string,ll> MSI;
typedef map <ll,ll> MII;
typedef pair<int, int> pii;
 
const int dx4[] = {-1, 0, 1, 0};
const int dy4[] = { 0, 1, 0,-1};
 
const int dx8[] = {-1, 0, 1, 0, -1,-1, 1, 1};
const int dy8[] = { 0, 1, 0,-1, -1, 1,-1, 1};
 
const int dxhorse[] = {-2, -2, -1, -1, 1, 1, 2, 2};
const int dyhorse[] = {1,  -1, 2 , -2, 2,-2, 1,-1};
 
template <typename T> inline T ItoS(T n){SS a; a<<n;return a.str();}
template <typename T> inline T TrailingZeros(T  n){ll cnt = 0;for(ll i=5; n/i>=1; i*=5) cnt += n/i;return cnt;}
template <typename T> inline T StoI(T s){ll sum=0;for(ll i=0; i<Sz(s); i++){s[i]-='0';sum=sum*10+s[i];}return sum;}
template <typename T> inline T binary_decimal(T n){ll decimal=0, i=0, rem;while (n!=0){rem = n%10;n/=10;decimal += rem*pow(2,i);++i;}return decimal;}
template <typename T> inline T LCM(T a,T b){return (a*b)/GCD(a,b);}
template <typename T> inline T maxi(T x, T y) { if(x>y) return x; else return y;}
template <typename T> inline T maxi(T x, T y,T z) { return maxi(maxi(x,y),z);}
template <typename T> inline T mini(T x, T y) { if(x<y) return x; else return y;}
template <typename T> inline T mini(T x, T y,T z) { return mini(mini(x,y),z);}
template <typename T> inline T GCD(T a,T b)   {ll t;while(a){t = a;a = b%a;b = t;}return b;}
template <typename T> inline T Pow(T base,T exp){ll result = 1;while (exp){if(exp&1)result*=base;exp>>=1;base*=base;}return result;}
template <typename T> inline T Mulmod(T a, T b, T c){ull x = 0,y = a%c;while(b>0){if(b&1) x = (x+y)%c;y = (y<<1)%c;b >>= 1;}return x;}
template <typename T> inline T Pow(T base,T exp,T mod){ull x = 1, y = base;while(exp>0){if(exp&1) x = Mulmod(x,y,mod);y = Mulmod(y,y,mod);exp >>= 1;}return x;}
template <typename T> inline T modulo(T a,T b,T c){ull x = 1 , y = a%c ;while( b>0 ){if(b%2) x = Mulmod(x,y,c) ;y=Mulmod(y,y,c);b/=2;}return x%c ;}
template <typename T> inline T BigMod(T a, T b, T m){if(!b)return 1;ll x=BigMod(a, b/2, m);x=(x*x)%m;if(b%2)x=(x*a)%m;return x;}
template <typename T> inline T EGCD(T a,T b,T &x,T &y){if(a == 0) {x = 0;y = 1;return b;}T x1, y1;T d = EGCD(b % a, a, x1, y1);x = y1 - (b / a) * x1;y = x1;return d;}
 
/****************** Prime Generator **********************/
 
const int N=1e7+10; int prime[20000010]; bool isprime[N]; int nprime;
template <typename T> void Sieve(T a) {nprime = 0;memset(isprime,true,sizeof(isprime));isprime[1]=false;for(int i=2;i<N;i++){if(isprime[i]){prime[nprime++]=i;for(int j=2;i*j<N;j++)isprime[i*j]=false;}}}
template <typename T> bool miller_rabin(T p, T itt) {if(p<2) return 0 ;if(p==2) return 1;if(p%2==0) return 0 ;ull s = p-1 ;while(s%2==0) s/=2;for(ll i=1;i<=itt;i++) {ull a = rand() % (p-1)+1 , temp = s ;ull mod = modulo(a,temp,(ull)p);while(mod!=1 and mod!=p-1 and temp!=p-1){mod = Mulmod(mod,mod,(ull)p);temp*=2;}if(temp%2==0 and mod!=p-1) return false ;}return true;}
template <typename T> inline T PrimeFactors(T n){ll cnt=0,sum=1;for(int i=0; prime[i]*prime[i]<=n and i<nprime;i++){cnt=0;while(n%prime[i]==0){cnt++;n/=prime[i];}sum*=(cnt+1);}if(n>1)sum*=2;return sum;}
 
/********************** Faster I/O *********************/
 
template <typename T> inline T scan(T &n) { n=0; bool negative=0; char c=gc(); while(c<'0'||c>'9') {if(c=='-') negative=1; c=gc();} while(c>='0'&&c<='9'){n=n*10+c-48;c=gc();} if(negative) n=~(n-1);}
template <typename T> inline T scan(T a,T b){scan(a);scan(b);}
template <typename T> inline T scan(T a,T b,T c){scan(a);scan(b);scan(c);}
template <typename T> inline T scan(T a,T b,T c,T d){scan(a);scan(b);scan(c);scan(d);}
template <typename T> void print(T n){if(n<0){pc('-');n=-n;}if(!n){pc('0');pc('\n');return;}char buff[12];int len=0;while(n) buff[len++]=n%10+48,n/=10;for(int i=len-1;i>=0;i--) pc(buff[i]);pc('\n');}
template <typename T> void print(T a, T b){print(a);print(b);}
template <typename T> void print(T a, T b, T c){print(a);print(b);print(c);}
template <typename T> void Print(T n){if(n<0){pc('-');n=-n;}if(!n){pc('0');return;}char buff[12];int len=0;while(n) buff[len++]=n%10+48,n/=10;for(int i=len-1;i>=0;i--) pc(buff[i]);}
 
/****************** Geometry *****************/
 
template <typename T> inline T PointDistanceHorVer(T x1,T y1,T x2, T y2) {return abs(x1-x2)+abs(y1-y2);}
template <typename T> inline T PointDistanceDiagonally(T x1,T y1,T x2, T y2) {return sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1));}
template <typename T> inline T PointDistanceMinimum(T x1,T y1,T x2, T y2) { T tmp1=abs(x1-x2); T tmp2=abs(y1-y2); T tmp3=abs(tmp1-tmp2); T tmp4=min(tmp1, tmp2); return tmp3+tmp4; }
template <typename T> inline T PointDistance3D(T x1,T y1,T z1,T x2,T y2,T z2) {return sqrt(square(x2-x1)+square(y2-y1)+square(z2-z1));}
 
template <typename T> inline T Cube(T a){return a*a*a;}
template <typename T> inline T RectengularPrism(T a,T b,T c){return a*b*c;}
template <typename T> inline T Pyramid(T base, T height){return (1/3)*base*height;}
template <typename T> inline T Ellipsoid(T r1,T r2,T r3) {return (4/3)*PI*r1*r2*r3;}
template <typename T> inline T IrregualarPrism(T base, T height){return base*height;}
template <typename T> inline T Sphere(T radius){ return (4/3)*PI*radius*radius*radius;}
template <typename T> inline T CylinderB(T base, T height){return base*height;} // base and height
template <typename T> inline T CylinderR(T radius, T height){return PI*radius*radius*height;} // radius and height
template <typename T> inline T Cone (T radius,T base, T height){return (1/3)*PI*radius*radius*height;}
 
/**>>>>>>>>>>>>>>>>>>> END <<<<<<<<<<<<<<<<<<**/
 
 
const int INF= 1e9+5;
 
int main(){
	int n;
	cin >> n;
	vector <int> dp(n);
	int t;
	cin >> t;
	for(int& b: dp){
		scanf("%d",&b);
	}
	VI hash(n,INF);
	hash[0] = 0;
	ForA(n){
		for(int a=i+1;a<=i+t;a=a+1){
			if(a<n){
				hash[a] = min(hash[a], hash[i] + abs(dp[i] - dp[a]));
			}
			
		}
	}
	cout << hash[n-1] << endl; 
    return 0;
}



Measured memory_bytes: 1408