#include <stdio.h>
int main()
{
    double x,y;
    scanf ("%lf",&x);
    if (x!=0)
    {
        if (x>0)
           y=1－x;
      
        else
           y=(1－x)*(1－x);
    }
     else
        y=2;
     printf("%lf\n",y);
     return 0;
}

谢谢