#include<iostream>
using namespace std;
int main()
{ double P =1.0;
  cout.precision(10);
  for (double x = 2; x <= 20000; x=x+2)
  {//cout << "x=" <<x <<endl;
   P=P*x*x/(x-1)/(x+1);
   //cout <<"P="<<P<<endl;
  }
  cout << " wallis PI = " <<P*2<<endl;

  double sum =0.0;
  double C = -1.0;
  for(double x=1.0; x<=100001.0; x=x+2)
  { //cout << "x=" << x << endl;
    C=-C;
    //cout << "C=" << C <<endl;
    sum=sum+C*1.0/x;
      }
   cout << "Leibnitz PI=" << sum*4 << endl;
  cin.get();
  return 0;
}