//95%-ban ChatGPT által készített kód

#include <iostream>
#include <string>

using namespace std;

bool isRainbowNumber(int number) {
    string str = to_string(number);
    int size = str.size();
    int breakPoint = 0;
    for (int i = 0; i < size - 1; i++) {
        if (str[i] < str[i + 1]) {
            breakPoint = i + 1;
        } else {
            break;
        }
    }
    for (int i = 0; i < breakPoint; i++) {
        if (str[i] >= str[i + 1]) {
            return false;
        }
    }
    for (int i = breakPoint; i < size - 1; i++) {
        if (str[i] <= str[i + 1]) {
            return false;
        }
    }
    return true;
}

int main() {
    int n;
    cin >> n;
    int count = 0;
    for (int i = 0; i < n; i++) {
        if (isRainbowNumber(i)) {
            count++;
        }
    }
    cout << count << endl;
    return 0;
}