CF596B Wilbur and Array

Wilbur the pig is tinkering with arrays again. He has the array $ a_{1},a_{2},...,a_{n} $ initially consisting of $ n $ zeros. At one step, he can choose any index $ i $ and either add $ 1 $ to all elements $ a_{i},a_{i+1},...\ ,a_{n} $ or subtract $ 1 $ from all elements $ a_{i},a_{i+1},...,a_{n} $ . His goal is to end up with the array $ b_{1},b_{2},...,b_{n} $ . Of course, Wilbur wants to achieve this goal in the minimum number of steps and asks you to compute this value.

The first line of the input contains a single integer $ n $ ( $ 1

Print the minimum number of steps that Wilbur needs to make in order to achieve $ a_{i}=b_{i} $ for all $ i $ .

In the first sample, Wilbur may successively choose indices $ 1 $ , $ 2 $ , $ 3 $ , $ 4 $ , and $ 5 $ , and add $ 1 $ to corresponding suffixes. In the second sample, Wilbur first chooses indices $ 1 $ and $ 2 $ and adds $ 1 $ to corresponding suffixes, then he chooses index $ 4 $ and subtract $ 1 $ .