Platforms - 3
In older games one can run into the next situation. The hero jumps along the platforms that hang in the air. He must move himself from one side of the screen to the other. When the hero jumps from one platform to the neighboring, he spends energy, where and are the heights where these platforms hang. The hero can make a super jump that allows him to skip one platform, but it takes him energy.
You are given the heights of the platforms in order from the left side to the right. Find the minimum amount of energy to get from the -st (start) platform to the -th (last).
Input
The first line contains the number of platforms . The second line contains integers — the heights of the platforms. Their absolute values are not grater than by absolute value.
Output
Print one integer — the minimum amount of energy.