#include <stdio.h>

class inf
{
public:
  int height;
  char name;
};

int main(void)
{


  inf a[3];
  scanf("%d", &a[0].height);
  scanf("%d", &a[1].height);
  scanf("%d", &a[2].height);
  a[0].name = 'A';
  a[1].name = 'B';
  a[2].name = 'C';

  for(int i=0; i<3; i++){
    for(int j=i+1; j<3; j++){
      if(a[i].height<a[j].height){
        inf temp = a[j];
        a[j] = a[i];
        a[i] = temp;
      }
    }
  }

  for(int i=0;i<3;i++){
    printf("%c\n", a[i].name);
  }
  return 0;

}