Problem:
Score : 100 points

Problem Statement

Snuke has a favorite restaurant.

The price of any meal served at the restaurant is 800 yen (the currency of Japan), and each time a customer orders 15 meals, the restaurant pays 200 yen back to the customer.

So far, Snuke has ordered N meals at the restaurant.
Let the amount of money Snuke has paid to the restaurant be x yen, and let the amount of money the restaurant has paid back to Snuke be y yen.
Find x-y.

Constraints

1 ≤ N ≤ 100

Input

The input is given from Standard Input in the following format:

N

Output

Print the answer.

Sample Input 1

20

Sample Output 1

15800

So far, Snuke has paid 16000 yen, and the restaurant has paid back 200 yen. Thus, the answer is 15800.

Sample Input 2

60

Sample Output 2

47200

Snuke has paid 48000 yen for 60 meals, and the restaurant has paid back 800 yen.

Solution in Ruby (2.3.3) (judge verdict: Accepted)

include Math
define_method :max, -> (a,b) { a > b ? a : b }
define_method :min, -> (a,b) { a < b ?  a : b }
define_method :swap, -> (a,b) { a, b = b, a }
define_method :rep, -> (num, &block) { num.times do |i| block.call(i) end }
define_method :repl, -> (st,en, &block) { st.upto en-1 do |i| block.call(i) end }
define_method :array, -> (size,init = nil) { Array.new(size){init} }
define_method :darray, -> (size1, size2, init = nil) { Array.new(size1){Array.new(size2){init}} }
define_method :gi, -> () { gets.split.map(&:to_i) }
define_method :gs, -> () { gets.chomp }
define_method :putall, -> (obj) { obj.each do |o| puts o end }


n = gi[0]

ans = n*800-200*(n/15)

puts ans