#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <iomanip>
#include <time.h>
#include <random>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
using namespace std;
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
int main() {
	string s;
	cin >> s;
	//-10
	long long ans = max(((int)s.length()-10)*9,0);
	if (s.length() >= 10) {
		ans += s[0] - '1';
		for (int i = 0;i < s.length() - 9;++i) {
			if (s[i] < s[0]) goto foo;
			if (s[s.length() - i - 1] < s[0]) goto foo;
		}
		ans++;
	foo:;
	}
	cout << ans << endl;
	return 0;
}