
function Main(input) {
    input = input.trim();
    // input = input.split("\n")
    // input = input.map(e=>e.split(" ").map(f=>parseInt(f)))
    if(input == "ABC"){
        console.log("ARC")
    }else{
        console.log("ABC")
    }
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
