Problem:
Score : 100 points

Problem Statement

Takahashi wants to print a document with N pages double-sided, where two pages of data can be printed on one sheet of paper.

At least how many sheets of paper does he need?

Constraints

N is an integer.

1 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer.

Sample Input 1

5

Sample Output 1

3

By printing the 1-st, 2-nd pages on the 1-st sheet, 3-rd and 4-th pages on the 2-nd sheet, and 5-th page on the 3-rd sheet, we can print all the data on 3 sheets of paper.

Sample Input 2

2

Sample Output 2

1

Sample Input 3

100

Sample Output 3

50

Solution in Ruby (2.3.3) (judge verdict: Runtime Error)

a = []
3.times do
    a << gets.split("\s").map(&:to_i)
end

a.flatten!

n = gets.to_i

n.times do
  b = gets.to_i
  if i = a.index(b)
    a[i] = -1
  end
end

if ((a[0] < 0 && a[1] < 0 && a[2] < 0) || (a[3] < 0 && a[4] < 0 && a[5] < 0) ||
  (a[6] < 0 && a[7] < 0 && a[8] < 0) || (a[0] < 0 && a[3] < 0 && a[6] < 0) ||
  (a[1] < 0 && a[4] < 0 && a[7] < 0) || (a[2] < 0 && a[5] < 0 && a[8] < 0) ||
  (a[0] < 0 && a[4] < 0 && a[8] < 0) || (a[2] < 0 && a[4] < 0 && a[6] < 0))
  print 'Yes'
else
  print 'No'
end