Problem:
Score : 100 points

Problem Statement

On the Planet AtCoder, there are four types of bases: A, C, G and T. A bonds with T, and C bonds with G.

You are given a letter b as input, which is A, C, G or T. Write a program that prints the letter representing the base that bonds with the base b.

Constraints

b is one of the letters A, C, G and T.

Input

Input is given from Standard Input in the following format:

b

Output

Print the letter representing the base that bonds with the base b.

Sample Input 1

A

Sample Output 1

T

Sample Input 2

G

Sample Output 2

C

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

STDIN.gets
s = STDIN.gets
acm = Array.new(s.length, 0)

flg = false
i = 0
s.chars do |c|
  if c == 'A'
    flg = true
  else
    if c == 'C' && flg
      acm[i-1] = 1
    end
    flg = false
  end
  i+=1
end

cache = {}
lines = STDIN.readlines
lines.each do |line|
  st, e = line.split(' ')
  key = "#{st}:#{e}"
  if c = cache[key]
    puts c
  else
    v = acm[st.to_i-1..e.to_i-2].inject(:+)
    cache[key] = v
    puts v
  end
end