#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <numeric>
#include <utility>
#include <tuple>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<int, int>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
template<typename T> bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; }
template<typename T> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

bool check(ll n) {
    vector<int> a;
    while (n) {
        a.push_back(n % 10);
        n /= 10;
    }
    bool ok = true;
    REP(i, 0, a.size()) {
        ok &= (a[i] == a[a.size() - 1 - i]);
    }
    return ok;
}

ll rev(ll n) {
    ll res = 0;
    while (n) {
        res = res * 10 + n % 10;
        n /= 10;
    }
    return res;
}

int digit(ll n) {
    int res = 1;
    do {
        res *= 10;
        n /= 10;
    } while (n);
    return res;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    ll n;
    cin, n;
    const ll base = 1000000001;
    n /= base;
    vector<ll> ans;
    for (ll i = 1; i < 1000010; i++) {
        if (check(i) && i <= n) {
            ans.push_back(i);
        }
        ll r = rev(i);
        int d = digit(i);
        if (i * d + r <= n) {
            ans.push_back(i * d + r);
        }
        if (i / 10 * d + r <= n) {
            ans.push_back(i / 10 * d + r);
        }
    }
    sort(ans.begin(), ans.end());
    ans.erase(unique(ans.begin(), ans.end()), ans.end());
    cout << ans.size() << endl;
    return 0;
}