#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <functional>
#include <cmath>
#include <complex>
#include <cctype>
#include <cassert>
#include <sstream>
#include <ctime>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> P;

#define INF (1<<29)
#define INFL (1ll<<60)
#define EPS (1e-8)
#define PI (acos(-1))
const ll MOD = 1000000007ll;

vector<string> v;

string to_str(ll x) {
	stringstream ss;
	ss << x;
	return ss.str();
}

void make(ll seed) {
	FOR(i, 1, 10) v.push_back(to_str(1000000001ll * seed * i));
	
	//cout << *(v.end() - 1) << endl;
}



int main() {
	ll n;
	cin >> n;
	
	FOR(i, 2, 9) make(powl(10, i) + 1);
	make(1);
	make(11);
	make(111);
	make(1111);
	make(11111);
	make(111111);
	make(1111111);
	make(11111111);
	make(111111111);
	
	make(101);
	make(1001);
	make(10001);
	make(100001);
	make(1000001);
	make(10000001);
	make(100000001);
	
	make(1);
	make(101);
	make(10101);
	make(1010101);
	make(101010101);
	
	make(1010101);
	make(10100101);
	make(101000101);
	
	make(10101);
	make(1001001);
	make(100010001);
	
	make(100101001);
	
	make(1111);
	make(11011);
	make(110011);
	make(1100011);
	make(11000011);
	make(110000011);
	
	make(11011011);
	
	make(110101011);
	make(110111011);
	
	make(1110111);
	make(11100111);
	make(111000111);
	make(111010111);
	make(111101111);
	
	make(101101);
	make(1011101);
	make(10111101);
	
	make(10011001);
	make(100111001);
	
	sort(ALL(v));
	v.erase(unique(ALL(v)), v.end());
	
	int ans = 0;
	REP(i, v.size()) {
		ll now;
		stringstream ss(v[i]);
		ss >> now;
		
		if (n < now) continue;
		ans++;
		
	}
	cout << ans << endl;
	
	return 0;
}