#include <iostream>
#include "cmath"

using namespace std;

int main()
{
    setlocale (LC_ALL, "rus_rus.1251");
    long double e, z = 0, sum = 0;
    cout << "Введите точность...\n";
    cin >> e;

    for (int n = 1; abs(z) < (e/10) ; n++)
        {
            z = (log(n)*log(n)*log(n)) / (n*(sqrtl(5*n+1)));
            sum = sum + z;
        }
    cout <<"Сумма = "<< sum <<endl;

return 0;
}