#include <iostream>
#include <cmath>
using namespace std;
int main(){
double sum = 0;
for(int i = 1; i <= 50; i++)
sum += 1 / pow(i,3);
cout << sum;
}
#include <iostream>
#include <cmath>
using namespace std;
int main(){
double sum = 0;
for(int i = 1; i <= 50; i++)
sum += 1 / pow(i,3);
cout << sum;
}