URI 1002-Area of a Circle_Solution

/*
Tanzila Islam
Southeast University
mail : tanzilamohita@gmail.com
Problem Link:
https://www.urionlinejudge.com.br/judge/en/problems/view/1002
*/

#include <iostream>
#include <iomanip>
using namespace std;
 
int main() {
double A, p = 3.14159, R;
cin >> R;
A = p * R * R;
cout << fixed << setprecision(4);
cout << "A=" << A << endl;
 
return 0;
}