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 FOR(i,n) for(int i=0; i<n; ++i)
#define FORR(i,a,n) for(int i=a; i<n; ++i)
#define ALL(c) (c).begin(), (c).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define UNIQ(c) (c).erase(unique(ALL((c))), end((c)))

typedef long long ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<VI> VVI;
typedef vector<VL> VVL;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;
 
int in() { int x; scanf("%d", &x); return x; }
ll lin() { ll x; scanf("%lld", &x); return x; }
void printfv(VI a){ int n = a.size(); FOR(i, n) cout << a[i] << " "; }

int main(void){

    char b;
    cin >> b;

    switch(b){
        case 'A': cout << 'T'; break;
        case 'C': cout << 'G'; break;
        case 'G': cout << 'C'; break;
        case 'T': cout << 'A'; break;
    }

    return 0;
}