#include<stdio.h>
#include<string.h>
void main()
{
    char bin[40];
    scanf("%d",&bin);
    for (int i = 0; bin[i] !='\0';i++)
    {
        if (bin[i] !='0' && bin[i] !='1')
        {
            printf("Invalid input");
        }
    }
    int n = strlen(bin);
    if (n > 32)
    {
        printf("Invalid input");
    }
    if (bin[0]=='0')
    {
        int value = 0;
        for (int i = 0;i < n; i++)
        {
            value = value * 2 + (bin[i]-'0');
        }
        printf("%d", value);
    }
    else
    {
        unsigned int value=0;
        for (int i = 0; i < n; i++)
        {
            value = value * 2 + (bin[i]-'0');
        }
        int signedvalue = (int)value-(1<<n);
        printf("%d", signedvalue);
    }
}