#include <iostream.h>
#include <math.h>


const double OneOverRootTwoPi = 0.398942280401433; 

// probability density for a standard Gaussian distribution
double NormalDensity(double x)
{
    return OneOverRootTwoPi*exp(-x*x/2);
}



// main function
void main ()
{
  
	double x; 

    cout << "Enter a value" << endl;
	cin >> x;

	cout << "probability density is " <<  NormalDensity(x) << endl; 


  
}