//
// Created by tamas on 9/8/23.
//

#include "bits/stdc++.h"
using namespace std;

string s;
int r = 0;

struct vmi {
    bool found_max;
    int val;
    int index;
    bool thing;
};

void f(vmi& dolog) {
    bool found_max = dolog.found_max;
    int val = dolog.val;
    int index = dolog.index;
    bool thing = dolog.thing;
    if (index == s.size()) {
        r++;
        return;
    }
    int num = s[index] - '0';
    if (found_max) {
        int m  = thing ? val : min(num, val);
        for (int i = 0; i <= m; i++) {
            vmi v = (vmi){true, i, index + 1, (bool)(thing | (i < num))};
            f(v);
        }
    }
    else {
        int m = thing ? 9 : min(num, 9);
        for (int i = 0; i <= m; i++) {
            vmi v = (vmi){i < val, i, index+1, (bool)(thing | (i < num))};
            f(v);
        }
    }
}

int main() {
    cin >> s;
    vmi v = (vmi){false, 0, 0, false};
    f(v);
    cout << r-1;
}