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)

/*																													   
 Templatka c++ Kacper Fis																							   																											   //
*/																													  
#include <functional>																							   
#include <bits/stdc++.h>																							   
																													   
using namespace std; 																								   
																													   
const int INF = 1000000001;																						   
const float PI = 3.14;																								   
typedef long long LL;																								   
																													   
typedef vector<int> vi;																								   
typedef list<int> li;																								   
typedef queue<int> qi; 																								   
typedef pair<int,int> ii; 																							   
typedef map<string,int> msi; //np msi['nazwa'] = 'liczba'															   
typedef vector<ii> vii; //vector par<int>, do tworzenia tablicy dla grafów wagowych #dijkstra #Bellman_Ford			   
typedef priority_queue< ii, vector<ii>, greater<ii> > pq; //kolejka priorytetowa vectorów par(top()=min) #dijkstra																													   																				   list<int>::iterator it;																								   
																				   
vector<ii>::iterator iter;																							   
																													   																				   
#define print_list(x) for(it = (x).begin(); it != (x).end(); it++) {cout << *it << " ";}							   
#define print_vector(x) for(it2 = (x).begin(); it2 != (x).end(); it2++) {cout << *it2 << " ";}						   
#define search_list(x) for(it = (x).begin(); it != (x).end(); it++)													   
#define search_vector(x) for(it2 = (x).begin(); it2 != (x).end(); it2++);											   
#define pb(x) push_back(x) 																							   
#define pf(x) push_front(x)																							   
#define mp(x, y) make_pair(x, y)                                                                                       
///////////////////////////////////////////////GLOBAL DEFINITIONS//////////////////////////////////////////////////////


///////////////////////////////////////////////FUNCTIONS/////////////////////////////////////////////////////////////


/////////////////////////////////////////////////////MAIN////////////////////////////////////////////////////////////////
int main(int argc, char* argv[])																					 
{ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);                  												       
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
	
	char c;
	cin >> c;
	if(c == 'A'){
		cout << 'T' << endl;
	}
	else if(c == 'T'){
		cout << 'A' << endl;
	}
	else if(c == 'G'){
		cout << 'C' << endl;
	}
	else cout << 'G' << endl;
	
	
	
	
	
	
	
	
	
	
	
	
    
	return 0;
}