#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
#include <algorithm>
using namespace std;
int main() {
float n;
cin >> n;
if (n <= 1) {
cout << "wrong data";
return 0;
}
float P = (1-1/2*2)*(1-1/3*3);
for (int i = 3; i <= n; ++i) {
P *= (1 - 1 / (n * n));
cout << P;
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
#include <algorithm>
using namespace std;
int main() {
float n;
cin >> n;
if (n <= 1) {
cout << "wrong data";
return 0;
}
float P = (1-1/2*2)*(1-1/3*3);
for (int i = 3; i <= n; ++i) {
P *= (1 - 1 / (n * n));
}
cout << P;
}