#include<bits/stdc++.h>
using namespace std;

int main()
{
    double t,l1,l2,sum=0,arx[100],ary[100],x;

    cout<<"Enter the number of iteration = ";
    cin>>t;
    cout<<"Enter upper limit = ";
    cin>>l2;
    cout<<"Enter lower limit = ";
    cin>>l1;
    x=(l2-l1)/t;
    arx[0]=l1;

    for(int i=1; i<=t; i++)
    {
        arx[i] = arx[i-1]+x;
    }

      for(int i=0; i<=t; i++)
    {
        ary[i] = sqrt((1-pow(arx[i],2)));
    }

      for(int i=1; i<t; i++)
    {
        sum = sum+2*ary[i];
    }
    sum = (sum+ary[0]+ary[5])*.5*x;


    cout<<"The summation is = "<<sum;



    return 0;
}