Semen has n candies and Yura m candies. At the same time they both eat one of their own candy as long as each of them has at least one candy. Determine how many candies will remain after they stop eating the sweets.

Input

Two integers n and m (1 ≤ n, m ≤ 109) - the number of candies at Semen and Yura respectively.

Output

Print the number of candies that will remain.