ktll-lab4.3

#include<iostream>
using namespace std;
int main()
{
	float n, x,s;
	s = 0;
	cout << ("nhap so x=");
	cin >> x;
	for (n = 1; n <= x ; n++)
	{
		s = s+1/(n*n);
	}
	cout << s << endl;
	system("pause");
	return 0;
}