#include <iostream> #include <string> using namespace std; bool isIncreasing(int num) { string s = to_string(num); for (int i = 0; i < s.size() - 1; i++) { if (s[i] > s[i+1]) { return false; } } return true; } int main() { int n; cin >> n; int count = 0; for (int i = 10; i <= n; i++) { if (isIncreasing(i)) { count++; } } cout << count << endl; return 0; }