
function Main(input) {
    input = input.split("");
    // console.log(input);
	if (input[0]===input[1] && input[0]===input[2]){
	    return console.log("No")
	}else{
	    return console.log("Yes");
	}
}
 
 
Main(require("fs").readFileSync("/dev/stdin", "utf8"));