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;
using ll = long long;
using P = pair<int,int>;
using Pl = pair<ll,ll>;
#define REP(i,n) for(ll i = 0;i < (ll)n;i++)
#define REPD(i,n) for(ll i = (ll)n - 1;i >= 0;i--)
#define ALL(x) (x).begin(),(x).end()
#define FILLl(n,first_dimension_size,value) fill((ll*)n,(ll*)(n+first_dimension_size),value)
#define FILL(n,first_dimension_size,value) fill((int*)n,(int*)(n+first_dimension_size),value)
#define INF (1 << 29)
#define MOD 1000000007
//int dx[4] = {1,0,0,-1};
//int dy[4] = {0,1,-1,0};


int main(){

  char c;
  cin >> c;
  if(c == 'A')cout << 'T' << endl;
  if(c == 'T')cout << 'A' << endl;
  if(c == 'C')cout << 'G' << endl;
  if(c == 'G')cout << 'C' << endl;


  return 0;
}