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

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