#include<stdio.h>
#include<string.h>
int main()
{
    char binaryString[33];
    scanf("%s", binaryString);
    if (!isValidBinary(binaryString)){
        printf("Invalid Input\n");
        return 0;
    }
    int len = strlen(binaryString);
    if (len > 32){
        printf("Invalid Input\n");
        return 0;
    }
    long long decimalValue = 0;
    for (int i = 0 ; i < len; i++){
        if (binarystring[i] == '1'){
            decimalValue += (long long)pow(2, len -1 - i);
        }
    }
    if (binaryString[0] == '1)'{
        decimalValue = decimalvalue - (long long)pow(2, len);
    }
    printf("%ld\n", decimalValue);
    return 0;
}