balbait (19)

#include <bits/stdc++.h>
using namespace std;
#define int int64_t

int getNrDigs(int x) {
    int r = 0;
    while (x) {
        r++;
        x /= 10;
    }
    return r;
}

signed main() {
    int n;
    cin >> n;

    int nrDigs = getNrDigs(n);
    int ans = 0;
    ans += (nrDigs - 1) * 9;

    for (int ch = '1'; ch <= '9'; ch++) {
        if (stoll(string(nrDigs, ch)) > n) {
            ans += int(ch - '0') - 1;
            break;
        }
    }

    cout << ans << endl;
    return 0;
}