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>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
template<class T> inline bool chmax(T& a, T b) {if (a < b) {a = b;return true;}return false;}

int main() {
    char b;
    cin >> b;
    if (b=='A'){
        cout << 'T' << endl;
    }
    else if (b=='T'){
        cout << 'A' << endl;
    }
    else if (b=='G'){
        cout << 'C' << endl;
    }
    else if(b=='C'){
        cout << 'G' << endl;
    }
}