function Main(input) {
	input = input.split(" ");
    input = input[0];
    
    var ans = "";	
	for(var i = 1; i <= input.length; i = i + 2){
	    ans += input[i -1]; 
	}
    console.log(ans);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));
