#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main()
{
    char bin[33];
    scanf("%32s", bin);
    for (int i = 0; bin[i]; i++)
    if (bin[i] != '0' && bin[i] != '1')
    {
        printf("Invalid Input\n");
        return 0;
    }
    int n = strlen(bin);
    int val = (int)strtol(bin, NULL, 2);
    if (bin[0] == '1' && n == 32)
        val -= (1U << 32);
    printf("%d\n", val);
    return 0;
}