//Zoos

// Sample code to perform I/O:

process.stdin.resume();
process.stdin.setEncoding("utf-8");
var stdin_input = "";

process.stdin.on("data", function (input) {
    stdin_input += input;                               // Reading input from STDIN
});

process.stdin.on("end", function () {
   main(stdin_input);
});

function main(input) {
    var data= input.toString().split("\n");
    process.stdout.write(check(data[0]));       // Writing output to STDOUT
}

// Warning: Printing unwanted or ill-formatted data to output will cause the test cases to fail



// Write your code here
// Sample code to perform I/O:
//Enter your code here
function check(data) {

    const n=data.length;
    let x = 0;
    let y = 0;

    for (let i=0; i<n; i++) {
        if (data[i]=="z") {
            x++ ;
        } else {
            if (data[i]=="o") {
                y++;
            } 
        }
    }

    if (2 * x == y) {
        return "Yes";
    } else { return "No";}


}