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

int main()
{
    char bin[40];
    scanf("%s", bin);
    
    int len = strlen(bin);
    
    for (int i = 0; i < len; i++)
    {
        if (bin[i] != '0' && bin[i] != '1')
        {
            printf("Invalid Input");
            return 0;
        }
   
}
if (bin[0] == '0')
{
    long long value = 0;
    for (int i = 0; i < len; i++)
    {
        value = value * 2 + (bin[i] - '0');
    }
    printf("%11d", value);
}
else
{
    unsigned long long value = 0;
    
    for (int i = 0; i < len; i++)
    {
        value = (value << 1) | (bin[i] - '0');
    }
    
    long long signedValue = value - ((unsigned long long)1 << len);
    
    printf("%11d", signedValue);
}