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 <stdio.h>
#include <stdlib.h>
int main(void){
  char s[100];
  char s1[100]="ABC";
  int i=0;
  int flag=0;
  scanf("%s",s);
  while(s[i]!='\0' && s1[i]!='\0'){
    if(s[i]!=s1[i]){
      flag=1;
      break;
    }
    i++;
  }
  if(flag==1){
    printf("ABC");
  }else if(flag==0){
    printf("ARC");
  }
  return 0;
}