"use strict";
// https://atcoder.jp/contests/abc158/tasks/abc158_a
function main(s) {
    let i = 1;
    for (let ch = s[0]; i < 3; i++) {
         if (ch !== s[i]) {
               break;
         }
    }
    console.log(i === 3? "No": "Yes");
}
main(require("fs").readFileSync("/dev/stdin", "utf8"));