A11637 | Friends Meeting

Two friends are on the coordinate axis $Ox$ in points with integer coordinates. One of them is in the point $x_{1}=a$ , another one is in the point $x_{2}=b$ .

Each of the friends can move by one along the line in any direction unlimited number of times. When a friend moves, the tiredness of a friend changes according to the following rules: the first move increases the tiredness by $1$ , the second move increases the tiredness by $2$ , the third — by $3$ and so on. For example, if a friend moves first to the left, then to the right (returning to the same point), and then again to the left his tiredness becomes equal to $1+2+3=6$ .

The friends want to meet in a integer point. Determine the minimum total tiredness they should gain, if they meet in the same point.

The first line contains a single integer $a$ ( $1<=a<=1000$ ) — the initial position of the first friend.

The second line contains a single integer $b$ ( $1<=b<=1000$ ) — the initial position of the second friend.

It is guaranteed that $a≠b$ .

Print the minimum possible total tiredness if the friends meet in the same point.