#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 200010;
const int mod = 1e18 + 7;
vector<int> f[N];
int power(int a, int b, int c) {
    int ans = 1;
    while (b) {
        if (b & 1) ans = ans * a % c;
        a = a * a % c, b >>= 1;
    } return ans;
}
int solve(string s, int mod) {
    int f[2] = {1, 0}, n = s.size();
    for (int i = 0; i < (n + 1) / 2; ++i) {
        int g[2] = {0, 0};
        for (int j = 0; j < 2; ++j) {
            int l = i ? 0 : 1, r = j ? 9 : (s[i] & 15);
            for (int k = l; k <= r; ++k) g[j || (k < r)] = (g[j || (k < r)] + f[j]) % mod;
        }
        f[0] = g[0], f[1] = g[1];
    }
    int ss = f[1];
    for (int i = 1; i < n; ++i) ss = (ss + power(10, (i - 1) / 2, mod) * 9 % mod) % mod;
    string nw; for (int i = 0; i < (n + 1) / 2; ++i) nw += s[i];
    for (int i = (n + 1) / 2; i < n; ++i) nw += s[n - i - 1]; ss += (nw <= s); return ss;
}
signed main() {
    cin.tie(0)->sync_with_stdio(false);
    int n;
    cin >> n;
    n /= 1000000001;
    cout << solve(to_string(n), mod) << '\n';
    return 0;
}