"use strict";
    
const main = arg => {
    const S  = arg.split("\n")[0].split("");
    let answer = [];
    
    for(let i in S) {
        if(i % 2 === 0) answer.push(S[i]);
    }
    
    console.log(answer.join(""));
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));