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 ABC122_A
#ifdef ABC122_A
// ABC122-A 

#pragma comment (linker, "/STACK:256000000")
#include "bits/stdc++.h"
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=int(a),i##_len=(b);i<i##_len;++i)
#define BUGAVOID(x) x
#define rep(...) BUGAVOID(_overload3(__VA_ARGS__,repi,_rep,_rep)(__VA_ARGS__))
#define sz(c) (int)(c.size())
#define all(c) c.begin(),c.end()
#define mp make_pair
#define write(x) cout<<(x)<<"\n"
using namespace std; typedef long long ll; typedef vector<int> vi; typedef vector<ll> vll;
template<class T, class U>using vp = vector<pair<T, U>>;
template<class T>using vv = vector<vector<T>>; template<class T, class U>using vvp = vv<pair<T, U>>;
template<class T>vv<T> vvec(const size_t n, const size_t m, const T v) { return vv<T>(n, vector<T>(m, v)); }
template<class T>bool chmax(T &a, const T &b) { if (a < b) { a = b; return 1; }return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b < a) { a = b; return 1; }return 0; }
constexpr ll pow2(const int n) { return 1ll << n; }
constexpr int INF = 1 << 28; constexpr ll LINF = 1ll << 60;
constexpr int MAX = 1e5 + 5; constexpr int MOD = 1e9 + 7; constexpr double EPS = 1e-6;
constexpr int dy[4] = { 0,1,0,-1 }; constexpr int dx[4] = { 1,0,-1,0 };
struct aaa { aaa() { cin.tie(0); ios::sync_with_stdio(0); }; }aaaa;
// 1. 問題よくよめえええええええええええええええええええええええええ
// 2. intオーバーフロー << * + あたり
// 3. 落ち着け

int N, M, H, W;
int ans;
string s;

int main() {
    char c;
    cin >> c;

    if (c == 'A') write("T");
    else if (c == 'T') write("A");
    else if (c == 'G') write("C");
    else write("G");
}

#endif