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: Runtime Error)

#include<stdio.h>
int main (void){
  int n,k,i,s,p,t,g=0,a[110];
    scanf("%d %d",&n,&k);
  for(i=0;i<k;i++){a[i]=0;}
  i=0;
  for(s=0;s<n;s++){  scanf("%d",&p);for(i=0;i<p;i++)  {scanf("%d",&t);a[t]=1;  }  }
  i=0;
  for(i=0;i<k;i++){  if(a[i]==0) g++ ; }
  printf("%d",g);
 return 0; 
}