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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
#include<assert.h>

using namespace std;

int main()
{
	string b;
	cin>>b;
	if(b=="A")
		cout<< "T"<< endl;
		else if(b=="T")
			cout<<"A"<< endl;
			else if(b=="C")
				cout<< "G"<< endl;
				else
					cout<< "C"<< endl;

  return 0;
}