Frog

There are $n$ stones, numbered from $1$ to $n$. For each $i(1\le i\le n)$, the height of the $i$-th stone is $h_i$. The frog initially sits on stone $1$. It repeats the following action several times to reach stone $n$: if the frog is on stone $i$, it can jump either to stone $i+1$ or to stone $i+2$. The cost of moving from the $i$-th to the $j$-th stone is $|h_i-h_j|$.

Find the minimum cost of moving the frog to stone $n$.

Input

The first line contains the number of stones $n(2\le n\le 10^5)$. The second line contains integers $h_1,h_2,...,h_n(1\le h_i\le 10^4)$.

Output

Print the minimum cost of moving the frog to stone $n$.

Examples