#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <functional>
#include <cmath>
#include <complex>
#include <cctype>
#include <cassert>
#include <sstream>
#include <ctime>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> P;
typedef vector<ll> vl;
typedef vector<vl> vvl;

#define INF (1<<29)
#define INFL (1ll<<60)
#define EPS (1e-8)
#define PI (acos(-1))
const ll MOD = 1000000007ll;

int main() {
	ll n;
	cin >> n;
	
	n /= 1000000001;
	
	int ans = 0;
	
	FOR(i, 1, 10) if (i <= n) ans++;
	
	for (ll i = 1; i * i <= n; i++) {
		stringstream ss;
		ss << i;
		
		string now, rev;
		ss >> now;
		rev = now;
		reverse(ALL(rev));
		
		if (now != rev) continue;
		now += rev;
		cout << now << endl;
		
		ss.clear();
		ss << now;
		
		ll num;
		ss >> num;
		
		if (num <= n) ans++;
	}
	cout << ans << endl;
	
	return 0;
}