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: Wrong Answer)

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

int main(void){
  int i,j,N,K,tmp1,ans[100]={0};
  scanf("%d %d",&N,&K);
  int *d=(int*)malloc(sizeof(int)*K);
  int **A;
  A=(int**)malloc(sizeof(int*)*K);
  for(i=0;i<K;i++)
    A[i]=(int*)malloc(sizeof(int)*N);
  
  for(i=0;i<K;i++){
    for(j=0;j<N;j++)
      A[i][j]=0;
  }
  
  for(i=0;i<K;i++){
    d[i]=0;
    scanf("%d",&d[i]);
    for(j=0;j<d[i];j++){
      scanf("%d",&tmp1);
      tmp1--;
      A[i][tmp1]=A[i][tmp1]+1;
    }
  }
  int cat=N;
  for(i=0;i<K;i++){
    for(j=0;j<d[i];j++){
      if(0==A[i][j])
	ans[j]=1;
    }
  }
  for(i=0;i<K;i++){
    if(1==ans[i])
      cat--;
  }
  printf("%d\n",cat);

  /*for(i=0;i<K;i++){
    for(j=0;j<N;j++)
      printf("%d",A[i][j]);
    printf("%d\n",ans[i]);
    putchar('\n');
    }*/
  return 0;
}