const reader = require("readline").createInterface({
  input: process.stdin,
  output: process.stdout
});
let lines = [];
reader.on("line", line => {
  lines.push(line);
});
reader.on("close", () => {
  let station = lines[0].split('')
  if (station[0] == station[1] && station[1] == station[2]) {
    console.log('No')
  } else {
    console.log('Yes')
  }
});