text: 'use strict';
  
  process.stdin.resume();
  process.stdin.setEncoding('utf-8');
  
  let inputString = '';
  let currentLine = 0;
  
  process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
  });
  
  process.stdin.on('end', _ => {
    inputString = inputString.trim().split('\n').map(string => {
      return string.trim();
    });
  
    main();
  });
  
  function readLine() {
    return inputString[currentLine++];
  }
  
  function main() {
    // Write your code here. Read input using 'readLine()' and print output using
    // 'console.log()'.
    const PI = Math.PI;
    let radius = readLine();
  
    // Print the area of the circle:
    console.log(PI * radius * radius);
  
    // Print the perimeter of the circle:
    console.log(2 * PI * radius);
  
    try {
      // Attempt to redefine the value of constant variable PI
      PI = 0;
      // Attempt to print the value of PI
      console.log(PI);
    }
    catch (error) {
      console.error('You correctly declared \'PI\' as a constant.');
    }
  }