#include <stdio.h>
int main()
{
int n, result;
scanf("%d", &n);
result = n & 1 ? n - (n - 1) / 2 : - n / 2;
printf("%d", result);
return 0;
}
#include <iostream>
#include <string>
using namespace std;
class Frog
{
public:
Frog() : color("green"){}
Frog(const string& _color) : color(_color){}
virtual void jump(){cout << "frog jumpped.\n";}
void showColor(){cout << color << endl;}
virtual ~Frog(){}
private:
string color;
};
class Toad : public Frog
{
public:
Toad() : Frog("green"){}
Toad(const string& _color) : Frog(_color){}
void jump(){cout << "toad jumpped.\n";}
void cry(){cout << "toad cried.\n";}
};
int main()
{
Frog* frog = new Toad("yellow");
Toad* toad;
frog->showColor();
frog->jump();
if(toad = dynamic_cast<Toad*>(frog))
toad->cry();
delete frog;
}
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