https://codeperfectplus.com/10-days-of-javascript-day-1

let_and_const.js

function main() {
    // Write your code here. Read input using 'readLine()' and print output using 'console.log()'.
    let r = readLine();
    const PI = Math.PI;
    // Print the area of the circle:
    console.log(PI * (r * r) );
    // Print the perimeter of the circle:
    console.log(2 * PI * r);
}