'use strict';
function Main(input) {
  let stations = input.split("");
  stations = stations.map(v => v.toUpperCase());
  
  const stationsLen = stations.length;
  const arr = [];
  for (let i = 0; i < stationsLen; ++i){
    arr.push(new Array(stationsLen).fill(false));
  }
  
  for (let i = 0; i < stationsLen; ++i) {
    for (let j = 0; j < stationsLen; ++j) {
      arr[i][j] = stations[i] !== stations[j];
    }
  }
  
  let hasBus = false;
  let len = arr.length;
  main: for (let i = 0; i < len; ++i) {
    for (let j = 0; j < len; ++j) {
      if ( arr[i][j] ) { 
        hasBus = true; 
        break main; 
      }
    }
  }
  console.log(hasBus ? 'Yes' : 'No');
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));