#include <iostream>
#define PI 3.14159
using namespace std;

int main() 
{
  // Step 1: Read in radius
  double radius;
  cout << "Enter a radius: ";
  cin >> radius;

  // Step 2: Compute area
  double area = PI * radius * radius;

  // Step 3: Display the area
  cout << "The area is ";
  cout << area << endl;

  return 0;
}