#include
using namespace std;
int main()
{
int x = 0, y = 0;
cin>> x;
if( x > 2 && x <= 10 )
{
y = x * ( x + 2 );
}
else if( x > -1 && x <= 2 )
{
y = 2 * x;
}
else if( x < -1 )
{
y = x - 1;
}
cout<< y <
话说,如果x>10呢?