#include <stdio.h>
#include <string.h>
#include <math.h>

#define ON 1
#define OFF 0

int
main (int argc, char *argv[])
{
 int flip = OFF;
 int i = 0;		// A counter variable
 int num = 0;
 int j  = 0;		// A counter variable
 char *bits = argv[1];	// The bits we want to flip

 // Check if the number is negative
 if (bits[0] == '1')
   {
     printf("-");
     flip = ON; 
   }

 // If we need to flip the bits
 if (flip == ON)
   {
     // Subtract 1
     if (bits[7] == '1')
       bits[7] = '0';
     else
       {
         // Sam's subtraction algorithm, implemented in C.
         for(i=7; bits[i] == '0';i--)
           bits[i] = '1'; 
         bits[i-1] = '0';
       }

     // Flip the bits
     for (i = 0; i<8; i++)
       // Note, by subtracting the value of '0', we convert '0' to 0
       // '1' to 1.
       bits[i] = !(bits[i] - '0') + '0';

     // Tell Sam how we feel
     flip = OFF;

   }

 // Turn into an integer
 for (i = 7; i >= 0; --i)
   {
     if (bits[i] == '1')
       num += pow (2, j);
     ++j;
   }

 printf ("%d\n", num);
 return 0;
}