#include<bits/stdc++.h>
using namespace std;
#define error .000005
double f(double x)
{
    double r;
    r=sqrt(1.0-(x*x));
    return r;
}

void Calculation(double a,double b)
{
    double

     n=5,sum=0,ans=0,ans1;
    do{
        ans1=ans;
        sum=0;
        double delx = (b-a)/n;
        for(int i=0;i<=n;i++)
        {
            double xx = a + (i*delx); /// x0 = a; x1= a + delx; x2= a + delx + delx;  x3= a + delx + delx + delx;........
            if(i==0 || i==n)          /// x0 = a; x1= a + delx; x1= a + 2*delx;       x1= a + 3*delx;....................
                sum +=  f(xx);
           else if (i % 2 != 0)
                sum+= 4 * f(xx);
           else
                sum+= 2 * f(xx);
        }
         ans = 0.5 * delx * sum;
        cout<<"When n = "<<n<<" then Area = "<<ans<<endl;
        n+=5;
    }while(abs(ans1-ans)>error);
}


int main()
{
 Calculation(0,1);
 return 0;
}