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

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