#include <iostream>
#include <string>
using namespace std;
int main(){
int n;
cin >> n;
int cnt = 0;
for (int i = 1; i <= n; i++) {
string s;
int x = i;
while(x > 0) {
s += char(x % 2 + '0');
x /= 2;
}
bool ok = true;
int len = s.size();
for(int j = 0; j < len / 2; j++) {
if(s[j] != s[len - 1 - j]){
ok = false;
break;
}
}
if(ok==true) cnt++;
}
cout << cnt << endl;
return 0;
}
