#include <stdio.h>
#include<string.h>
#include<ctype.h>
void main()
{
    char bin[40];
    scanf("%s",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 signed value=(int)value-(1<<n);
    printf("%d",signed value);
}
}