#include<bits/stdc++.h>
using namespace std; 
int main()
{
	int n;
	cin>>n;
	int cnt=0;
	for(int i=1;i<=n;i++)
	{
		int t=i;
		string s;
		while(t)
		{
			s=s+char(t%2+'0');
			t/=2;
		}
		string s1=s;
		reverse(s1.begin(),s1.end());
		if(s1==s)
		{
			cnt++;
		} 
	}
	cout<<cnt;
	return 0;
}