```
#include <bits/stdc++.h>
using namespace std;
double l, s, x, n;
int main() {
cin >> l >> s >> x;
n = l / ((x + s) / 2 + s);
cout << fixed << setprecision(6) << ((x + s) / 2 * n) / x + n;
return 0;
}
```
by Alan2010 @ 2022-09-24 19:48:59
谢谢
by Habseligkeit @ 2022-09-24 20:45:46