'use strict'
function main(input) {
	let words = input;
  	let even = "";
  	for(let i = 0; i < input.length; i++) {
    	if(i % 2 === 1) {
        	continue;
        }else{
          even += words[i];
        }
    }
     console.log(even);
}
main(require("fs").readFileSync("/dev/stdin","utf8"))