/** libraries */
#include <iostream>
#include <cmath>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
/** libraries */
using namespace std;
/** defines */
#define ll long long
#define ld long double
#define yes cout << "YES" << "\n"
#define no cout << "NO" << "\n"
/** defines */
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
ld x;
cin >> x;
if(x < 5)
cout << sin(2*x + 3);
else if(x < 8)
cout << 3*x + 2 * pow(x,3);
else
cout << (3*x-2)/(1 + pow(x,2));
}
