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 (GCC 9.2.1) (judge verdict: Wrong Answer)

/* ex 5_4
   Kohei_Suzuki */

#include <stdio.h>
#define SIZE 50

int main(void){
    int count=0, ans=0;
    char sequence[SIZE], *ptr;
    //ptr: sequenceの各要素へのポインタ


    scanf("%s", sequence); //入力受取

    ptr = &sequence[0]; //ポインタへの代入

    // ACGT文字列の長さを求める
    while(*ptr){
        if(*ptr == 'A' || *ptr == 'C' || *ptr == 'G' || *ptr == 'T'){
            
            //A,T,C,Gのいずれからなcountを増やす
            count++;

            //これまでの長さの最大より大きければ更新
            if(count > ans){
                ans = count;
            }
        }
        else{
            //途切れたらcountを初期化
            count = 0;
        }
        ptr++;
    }

    printf("%d\n",ans);
    return 0;
}