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

int main()
{
    char bin[33];
    scanf("%s",bin);
    for (int i = 0; bin[i]; i++){
        if (bin[i] != '0' && bin[i] != '1'){ 
    printf("Invalid Input");
    return 0;
}
}
int len = strlen(bin);
int num = (int)strol(bin, NULL, 2);
if (bin[0] == '1' && len == 32)
num -= (1u << 32);
printf("%d", num);
return 0;
}