#include <stdio.h>
#include <string.h>
#include <math.h>
int main(){
    char bin[33];
    scanf("%s", bin);
    int len = strlen(bin);
    for ( int i = 0; i < len; i++)
    {
        if (bin[i] !='0'&& bin[i] !='1'){
            printf("Iinvalid Input");
            return 0;
        }
    }
    
    if (bin[0] == '0'){
        for(int i=0;i<len;i++)
        result = result * 2 + (bin[i]-'0');
    }
    printf("%d\n",result);
    else{
        unsigned int result =0;
         for(int i=0;i<n;i++){
        result = result*2+(bin[i]-'0');
        value -= (1LL<<n);
    }
    int signedresult =reslut-(1U << len);
    printf("%d\n",signedresult);
    }
    return 0;
    
}