// Slower C++ solution:
/**       In the name of Allah, the Gracious, the Merciful.

*               Praise be to Allah, Lord of the Worlds.

*               **************************************

*

*    I have not failed, I have just found 1000 WAYS that won't work.

*                 __________________________________

*                  Author  : Abd El-Twab  M. Fakhry

*                 __________________________________

*/



#include <ext/rope>

#include <bits/stdc++.h>

#include <ext/pb_ds/tree_policy.hpp>

#include <ext/pb_ds/assoc_container.hpp>



#define  print(arr, l, r)    for(int i = (l); i < (r); cout << arr[i++] << " \n"[i == r])

#define  read(arr, l, r)     for(int i = (l); i < (r); cin >> arr[i++])

#define  repr(i, r, l)       for (int i = r; i > l; i--)

#define  rep(i, l, r)        for (int i = l; i < r; i++)

#define  Unique(n)           (n).erase(unique(all(n)), (n).end())

#define  all(a)              a.begin() , a.end()

#define  RT(n)               return cout << (n) << endl, 0;

#define  sz(a)               (int)a.size()

#define  endl                '\n'

#define  D(x)                cout << #x << " = " << (x) << '\n'

#define  F                   first

#define  S                   second

#define  PB                  push_back

#define  EB                  emplace_back

#define  lsb(x)              (x & -x)

#define  get(n)              find_by_order(n)

#define  sqrt(n)             sqrtl(n)

#define  pow(a, b)           powl(a, b)

#define  indexOf(n)          order_of_key(n)

#define  isPowerOfTwo(x)     (x && !(x & (x - 1)))



using namespace std;

using namespace __gnu_pbds;

using namespace __gnu_cxx;



typedef long long            ll;

typedef unsigned long long   ull;



/**---------------------->>  Constants  <<-----------------------**/



const double    Pi      = 2 * acos(0.0),    Euler = 2.71828182845904523536,

                Epsln   = 1e-9,           GoldenR = (1 + sqrtl(5.0)) / 2;



const ll        MgcPrim = 2305843009213693951;

const int       MxsZ    = (int)1e5 + 9,        oo = 0x3f3f3f3f,

 		        ModB2   = (1 << 30) + 7,   ModBT7 = (int)1e9 + 7, ModBT = (int)1e9;



/**---------------->>  Functions & Shortcuts  <<-----------------**/



template <class T>

T Gcd(T a, T b) { return b ? Gcd(b, a % b) : a; }



template <class T>

T Lcm(T a, T b) { return a / Gcd(a, b) * 1ll * b; }



template <class T> /** Phi(a * b) = Phi(a) * Phi(b) where a and b Prime Factors and k their power **/

T Phi(T a, T k) { return pow(a, k - 1) * (a - 1); }



template <class T>

using indexed_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update >;



template <class T>

using matrix = vector < vector <T> >;



template <class T>

using min_heap = priority_queue < T, vector <T>, greater <T> >;



/** Watch **/



template <class T>

string ToString(T x) { stringstream sout; sout << x; return sout.str(); }



#ifdef BFS

int dx8[8] = { 1, -1, 0, 0, 1, 1, -1, -1 }, dx4[4] = { 0, 0, 1,-1};

int dy8[8] = { 0, 0, 1, -1, 1, -1, 1, -1 }, dy4[4] = { 1,-1, 0, 0};

#endif // BFS



/**------------------>>  Fast input / output  <<-----------------**/



void Fast()

{

    cin.sync_with_stdio(0);

    cin.tie(0);cout.tie(0);

    cin.exceptions(cin.failbit);

}



/**----------------->>  input / output Files  <<-----------------**/



void File()

{

    #ifdef FIO

    freopen("input.in", "r", stdin);

    freopen("output.out", "w", stdout);

   	#endif // FIO

}



/**------------------>>  Initialization gap  <<------------------**/



int n, a[MxsZ], dp[MxsZ];



int Frog(int nx)

{

    if(~dp[nx]) return dp[nx];

    return dp[nx] = min(Frog(nx - 1) + abs(a[nx] - a[nx - 1]), Frog(nx - 2) + abs(a[nx] - a[nx - 2]));

}



inline void Solve()

{

    memset(dp, -1, sizeof dp); memset(a, 0, sizeof a);



    cin >> n; read(a, 0, n);

    dp[0] = 0; dp[1] = abs(a[0] - a[1]);



    cout << Frog(n - 1) << endl;

}



/**------------------------->>  Main  <<-------------------------**/



int main()

{

    Fast(); File(); Solve();

}


// Faster C++ solution for the same problem (measured speedup: 1.7905147529725511x):
#include "bits/stdc++.h"



#define ll long long

#define ull unsigned long long

#define ld long double



#define tiii tuple < int, int, int >

#define pii pair < int, int >

#define pll pair < ll, ll >

#define pci pair < char, int >

#define psi pair < string, int >

#define pis pair < int, string >



#define vi vector < int >

#define vd vector < double >

#define vld vector < ld >

#define vll vector < ll >

#define vs vector < string >

#define vc vector < char >

#define vpi vector < pii >

#define vpll vector < pll >

#define vpis vector < pis >



#define pb push_back

#define mt make_tuple

#define gt0 get < 0 >

#define gt1 get < 1 >

#define gt2 get < 2 >



#define pi acos(-1)



#define fast ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)



using namespace std;



const int maxn = 1e5 + 5;

const int mod = 1e9 + 9;



ll a[maxn], f[maxn];



int main()

{

    //freopen("input.txt", "r", stdin);

    //freopen("output.txt", "w", stdout);



    fast;



    int n, k = 2;



    cin >> n;



    for(int i = 1; i <= n; i++) cin >> a[i];



    f[n] = 0;



    for(int i = n - 1; i > 0; i--){

        f[i] = 1e18;



        for(int j = 1; j <= k; j++){

            if(i + j > n) continue;



            f[i] = min(f[i], f[i + j] + abs(a[i] - a[i + j]));

        }

    }



    cout << f[1] << endl;



    return 0;

}