PROGRAMMING:Psychological shadow area

This is a mental shadow area map. We all think we can move forward at a constant speed (blue line in the picture), while in the late stage of procrastination, we tend to perform the crazy rush at the last moment (red line in the picture). The area enclosed by the red and blue lines is the psychological shadow area when we do our homework.
Now give the coordinates of the red inflection point $$(x, y) $$, ask you to calculate the psychological shadow area.
###Input format:
Input two positive integers, $$x $$and $$y $$no more than 100 in one line, and ensure that there is $$x > y $$. It is assumed that the maximum values of abscissa and ordinate (i.e. deadline and final completion) are 100.
###Output format:
Output the mental shadow area in one line.
Friendly reminder: area of triangle = length of bottom x height / 2; Rectangle area = bottom edge length x height. I think it's too complicated. It's a 5-point subtraction test
###Input example:
```in
90 10
```
###Output example:
```out
four thousand
```







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