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<bits/stdc++.h>
using namespace std;
int main()
{
    ios_base::sync_with_stdio(false); 
    cin.tie(NULL);  
    int n,k;
    cin>>n>>k;
    int arr[n] = {0};
    while(k--)
    {
        int d;
        cin>>d;
        while(d--)
        {
            int x;
            cin>>x;
            arr[x-1]++;
        }
    }
    int ans = 0;
    for(int i = 0;i<n;i++)
    {
        if(arr[i]==0)
        {
            ans++;
        }
    }
    cout<<ans;
    return 0;
}