const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    // Write your code here
    // 方1 使用正则,会超时
    let line = await readline();
    // let str = '';
    // while(str!==line){
    //     str = line;
    //     line = line.replace(/([a-z])\1{1}/g,'')
    // }
    // console.log(str?str:0)
    //方2,遍历一次的方式
    let arr = [];
    line = line.split('');
    let len = line.length;
    arr[0] = line[0];
    for(let i =1;i<len;i++){
        if(line[i]===arr[arr.length-1]){
            arr.pop()
        }else{
            arr.push(line[i])
        }
    }
    console.log(arr.length?arr.join(''):0)
}()