407148: GYM102697 119 Division One

You recently performed well in an online Codeforces contest, and you became part of "Division 1" on Codeforces. However, you're not sure that it will last. If you have a rating of 1900 or higher you're considered Division 1, otherwise, you're considered Division 2.

In each contest after you became Division 1, you didn't perform very well. Thus, your rating will decrease by 50 in each contest. Given your start rating, figure out how many contests it will take for you to become Division 2.

For example, if your start rating was $$$1970$$$, your rating would be $$$1920$$$ after the first contest, and after the second contest your rating would be $$$1870$$$, and you would become Division 2.

The only line of input contains a single positive integer $$$n$$$: your rating after the recent good contest.

Output a single positive integer $$$c$$$: the number of contests that you can still do before you become Division 2.

1970

2

2035

3

3549

33