da

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

int main() {

    int n;
    double sum = 1.0000;

    cout << "Broj? ";
    cin >> n;
    cout << endl;
    while(n>1) {
        if(n%2==0){
            sum -= 1 / (n*n);
            cout << "#Da# ";
        }
        else {
            sum += 1 / (n*n);
            cout << "#Ne# ";
        }

        n--;
    }
    cout << setprecision(3) << sum;

    system("pause");
    return 0;
}