#include <iostream.h> 
const double pi = 3.14159;
// Define the cylinder class:
class cylinder {
  public: double radius, length;
          double volume ( ) {return pi * radius * radius * length;}
};
// Define cylinder array:
cylinder oil_tanks[100];
main ( ) {
  // Declare various variables:
  int limit, counter;
  double sum = 0.0;
  // Read numbers and write them into array:
  for (limit = 0;                       ///
       cin >> oil_tanks[limit].radius   ///
           >> oil_tanks[limit].length;  ///
       ++limit)                         ///
    ;                                   ///
  // Compute volumes:
  for (counter = 0; counter < limit; ++counter)
    sum = sum + oil_tanks[counter].volume ( );
  // Display sum:
  cout << "The total volume in the "
       << limit << " storage tanks is "
       << sum << endl;
}