#include <iostream>
#include <cmath>
#include <conio.h>
using namespace std;

int main() {

    double e, x, sum = 0, s, fact;
    int i, k = 0;

    cout << "x = ";
    cin >> x;

    cout << "e = ";
    cin >> e;

    do
    {
        k++;
        fact = 1;
        for (i = 1; i <= k; ++i)
        fact *= i;

        s = pow(-1.0, k) * pow(0.5 * x, 2.0 * k + 1) / pow(fact, 2) / (k + 1);
        sum += s;
        }
    while (s > e);

    cout << "summa ravha " << sum;

 getch ();
 return 0;
}