Double Helix

题目描述

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 $b$.

输入格式

Input is given from Standard Input in the following format: $b$

输出格式

Print the letter representing the base that bonds with the base $b$.

A

T

G

C

提示

$b$ is one of the letters $A$，$C$，$G$ and $T$.

标签: AtCoder|abc122A

来源

AtCoder|abc122A