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)

#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
#define fi first
#define se second
#define pb push_back

using namespace std;
const long long MOD = (long long)1e9 + 7;

char c;

int main()
{
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin >> c;
    switch (c) {
        case 'A': c = 'T';break;
        case 'T': c = 'A';break;
        case 'C': c = 'G';break;
        case 'G': c = 'C';
    }
    cout << c << "\n";
	//system("pause");
	return 0;
}