Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.

Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.

Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.

Input

The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.

Output

Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.

Examples

Input

10


Output

10


Input

123


Output

113

Note

In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.

In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.StringTokenizer;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author pttrung
 */
public class B {

    public static boolean circle;

    public static void main(String[] args) throws FileNotFoundException {
        PrintWriter out;

        Scanner in = new Scanner();
        //out = new PrintWriter(new FileOutputStream(new File("output.txt")));
        out = new PrintWriter(System.out);
        int n = in.nextInt();

        if (n < 100) {
            out.println(n);
        } else {
            int start = 100;
            int index = 3;
            HashSet<Long> set = new HashSet();
            while (start <= n) {
                for (int i = 0; i < 10; i++) {
                    for (int j = i; j < 10; j++) {
                        cal(index, 0, i, j, 0, n, set);
                    }
                }
                start *= 10;
                index++;
            }

            out.println(set.size() + 99);
        }
        out.close();

    }

    public static void cal(int digit, int index, int x, int y, long val, int bound, HashSet<Long> set) {
        if (digit == index) {
            if (val <= bound) {

                set.add(val);
            }
            return;
        }
        if (index == 0) {
            if (x > 0) {
                cal(digit, index + 1, x, y, x, bound, set);
            }
            if (y > 0) {
                cal(digit, index + 1, x, y, y, bound, set);
            }
        } else {
            cal(digit, index + 1, x, y, val * 10 + x, bound, set);
            cal(digit, index + 1, x, y, val * 10 + y, bound, set);
        }
    }

    public static class Node {

        int x, y;

        public Node(int x, int y) {
            this.x = x;
            this.y = y;
        }
    }

    public static Line getLine(Point a, Point b) {
        int c = (a.x - b.x);
        int d = (a.y - b.y);
        if (c == 0) {
            return new Line(1, 0, -a.x);
        } else if (d == 0) {
            return new Line(0, 1, -a.y);
        } else {
            double rate = (double) (-d) / c;

            double other = ((double) rate * a.x) + a.y;
            //System.out.println(a + "|" + b + ": " + rate + " " + other);
            return new Line(rate, 1, -other);
        }
    }

    public static class Line {

        double a, b, c;

        public Line(double a, double b, double c) {
            this.a = a;
            this.b = b;
            this.c = c;
        }

        @Override
        public int hashCode() {
            int hash = 7;
            hash = 47 * hash + (int) (Double.doubleToLongBits(this.a) ^ (Double.doubleToLongBits(this.a) >>> 32));
            hash = 47 * hash + (int) (Double.doubleToLongBits(this.b) ^ (Double.doubleToLongBits(this.b) >>> 32));
            hash = 47 * hash + (int) (Double.doubleToLongBits(this.c) ^ (Double.doubleToLongBits(this.c) >>> 32));
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Line other = (Line) obj;
            if (Double.doubleToLongBits(this.a) != Double.doubleToLongBits(other.a)) {
                return false;
            }
            if (Double.doubleToLongBits(this.b) != Double.doubleToLongBits(other.b)) {
                return false;
            }
            if (Double.doubleToLongBits(this.c) != Double.doubleToLongBits(other.c)) {
                return false;
            }
            return true;
        }

        @Override
        public String toString() {
            return a + " " + b + " " + c;
        }
    }

    static class FT {

        int[] data;

        FT(int n) {
            data = new int[n];
        }

        void update(int index, int val) {
            // System.out.println("UPDATE INDEX " + index);
            while (index < data.length) {
                data[index] += val;
                index += index & (-index);

                //    System.out.println("NEXT " +index);
            }
        }

        int get(int index) {
            //  System.out.println("GET INDEX " + index);
            int result = 0;
            while (index > 0) {
                result += data[index];
                index -= index & (-index);
                // System.out.println("BACK " + index);
            }
            return result;
        }
    }

    public static double dist(Point a, Point b) {
        double val = (a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y);
        return Math.sqrt(val);
    }

    public static class Point {

        int x, y;

        public Point(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public String toString() {
            return x + " " + y;
        }
    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static long pow(int a, int b) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2);
        if (b % 2 == 0) {
            return val * val;
        } else {
            return val * val * a;
        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long lcm(long a, long b) {
        return a * b / gcd(a, b);
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new FileReader(new File("output.txt")));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}