'use strict';
const p = s => console.log(s);
// let a,b,c,d;
// [a,b,c,d] = input[0].trim().split(" ").map(i => parseInt(i));

function main(input) {
  let S = input[0].trim().split("");

  S[1] === 'B' ? p('ARC') : p('ABC');
}
main(require('fs').readFileSync('/dev/stdin', 'utf8').trim().split("\n"));
