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>

std::pair<int,int> tmp[100000];

int main(){
  std::string b;
  std::cin>>b;
  for(int i=0;i<(int)b.length();++i){
    if(b[i]=='A'){
      std::cout<<'T';
    }else if(b[i]=='C'){
      std::cout<<'G';
    }else if(b[i]=='G'){
      std::cout<<'C';
    }else if(b[i]=='T'){
      std::cout<<'A';
    }
  }
  std::cout<<std::endl;
  return 0;
}