Problem G
Draga Frá

Image from pickpik.com/

Gluggagægir is looking for his friend Atli. Initially, all windows had their curtains drawn. He has already drawn open many window curtains to try to find Atli, but so far without success. He asks you to write a program for him which will tell him how many curtains are remaining.

Input

Input consists of two lines. The first line contains one integer $n$, the total number of windows initially covered by curtains. The second line contains one integer $m$, the total number of window curtains that have been drawn open.

Output

The total number of windows covered by curtains.

Scoring

8
4

4

10
5

5

321
123

198