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 (Clang 10.0.0) (judge verdict: Runtime Error)

#include<stdio.h>

int main(){
	int n, m, i, j, count=0;
	scanf("%d %d", &n, &m);
	int h[n], a[m], b[m], counter[n], no[n];
	for(i=0; i<n; i++){
		scanf("%d", &h[i]);
		counter[i]=0;
		no[i]=0;
	}
	for(i=0; i<m; i++){
		scanf("%d %d", &a[i], &b[i]);
		no[a[i]-1]=1;
		no[b[i]-1]=1;
	}
	for(i=0; i<m; i++){
		if(h[a[i]]>h[b[i]]){
			counter[a[i]-1]=1;
			counter[b[i]-1]=0;
		}else if(h[a[i]]<h[b[i]]){
			counter[b[i]-1]=1;
			counter[a[i]-1]=0;
		}
	}
	for(i=0; i<n; i++){
		if(counter[i]==1&&no[i]==0){
			count++;
		}
	}
	printf("%d", count);

	return 0;
}