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 C (GCC 9.2.1) (judge verdict: Accepted)

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

int main(void)
{
  int ret = 0;
  int next = 0;
  char str[4];
  char contest[][4] = {"ABC","ARC"};
  
  /* input S */
  ret = scanf("%s", str);
  
  /* Jude */
  if (strcmp(str, contest[0]) == 0) {
    next = 1;
  } else if (strcmp(str, contest[1]) == 0) {
    next = 0;
  } else {
    return -1;
  }
  
  /* output contest */
  printf("%s", contest[next]);
  
  return 0;
}