Problem:
Score : 100 points

Problem Statement

AtCoder Inc. holds a contest every Saturday.

There are two types of contests called ABC and ARC, and just one of them is held at a time.

The company holds these two types of contests alternately: an ARC follows an ABC and vice versa.

Given a string S representing the type of the contest held last week, print the string representing the type of the contest held this week.

Constraints

S is ABC or ARC.

Input

Input is given from Standard Input in the following format:

S

Output

Print the string representing the type of the contest held this week.

Sample Input 1

ABC

Sample Output 1

ARC

They held an ABC last week, so they will hold an ARC this week.

Solution in Pascal (FPC 2.6.2) (judge verdict: Accepted)

var
 s:string[3];//省空间
begin
 readln(s);//读入s
 write('A');//先输出前一个字母
 if s[2]='B' then write('R')//如果为B，输出R
             else write('B');//否则输出B
 write('C');//输出最后一个
end.