SOC 2

#include <iostream>
#include <conio.h>
#include <string.h>

using namespace std;

int main()
{
    int i, r;
    char n[9];
    cin>>n;
    i = strlen(n)-1;
    r = n[i] - '0';
    i--;
    while(i > 0)
    {
        if(n[i] == '0')
            r = r*2+0;
        if(n[i] == '1')
            r = r*2+1;
        i--;
    }
    cout<<r;
    return 0;
}