#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
const long long INF = 1000000000000000;
int main(){
	int N;
	cin >> N;
	vector<long long> Y(N);
	for (int i = 0; i < N; i++){
		cin >> Y[i];
	}
	vector<long long> dp(N + 1, INF);
	dp[0] = 0;
	for (int i = 0; i < N; i++){
		if (i + 2 <= N){
			dp[i + 2] = min(dp[i + 2], dp[i] + Y[i + 1] - Y[i]);
		}
		if (i + 3 <= N){
			dp[i + 3] = min(dp[i + 3], dp[i] + Y[i + 2] - Y[i]);
		}
	}
	cout << dp[N] << endl;
}