#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
#include <iomanip>

using namespace std;

ofstream out;

int a;
double tmp;

double mtrx[100][2];
vector <float> our_coord;

void pushVector();
void fillMatrix();
void workWithMltrix();

int main() {


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


    cin >> a;

    pushVector();
    fillMatrix();

    mtrx[1][0] = 0;
    mtrx[1][1] = abs(our_coord[0] - our_coord[1]);

    workWithMltrix();

    out.open("out.txt");
    out << fixed;
    out << setprecision(2) << mtrx[a - 1][1];
    out.close();

    return 0;
}

void pushVector() {
    int i = 0;

    while (i < a) {
        i++;
        cin >> tmp;
        our_coord.push_back(tmp);
    }
}

void fillMatrix() {

    int i = 0;

    while (i < a) {
        i++;
        mtrx[i][0] = 1000;
        mtrx[i][1] = 1000;
    }
}

void workWithMltrix() {

    for (int i = 1; i < a - 1; i++) {
        mtrx[i][0] = mtrx[i - 1][1];
        mtrx[i + 1][1] = fmin(mtrx[i][0], mtrx[i][1]) + ( abs(our_coord[i] - our_coord[i + 1]));
    }
}