#include<bits/stdc++.h>
using namespace  std;
int n,sum,a[999999],xb;
int  main( ) 
{
    cin>>n;
    for (int i=1;i<=n;i++)
    {
        xb=0;
        int it=i;
        while (it!=0)
        {
            a[++xb]=it%2;
            it/=2;
        }
        int ok=1;
        for (int j=1;j<=xb/2;j++)
        {
            if (a[j]!=a[xb+1-j])
            {
                ok=0;
                break;
            }
        }
        if (ok)
            sum++;
    }
    cout<<sum;
    return 0;   
}