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.*;
import java.util.*;
import java.math.BigInteger;
/*
 * This file was created by ayush in attempt to solve the problem problems
 */
public class main {
    int ans=0;
    int n=0;

    public boolean isLucky(int n){
    	int x=-1;
	int y=-1;
	char[] temp = Integer.toString(n).toCharArray();
	for(int i=0;i<temp.length;i++){
		if(x==-1){
			x=temp[i]-'0';
		}else if(temp[i]-'0'==x){
			continue;
		}else if(y==-1){
			y=temp[i]-'0';
		}else if(temp[i]-'0'==y){
			continue;
		}else{
			return false;
		}
	}
	return true;
    }
    public void dfs(int inp){
	if(inp>0 && inp<=n)ans++;
	if(inp>=1000000000)return;
	for(int i=0;i<=9;i++){
		if(inp*10+i>0 && isLucky(inp*10+i)){
			dfs(inp*10+i);
		}
	}
    
    } 
    public void solve( PrintWriter out) {
	
    }

    public static void main(String[] args) throws Exception {
	
        FastScanner in = new FastScanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
       
	
        Date t1 = new Date();
        main solver = new main();
	solver.n=in.nextInt();
//	for(int i=1;i<=123;i++){
//		out.println(i+": "+solver.isLucky(i));
//	}
	
        solver.dfs(0);
	out.println(solver.ans);
        out.flush();
        Date t2 = new Date();
        System.err.println(String.format("Your program took %f seconds", (t2.getTime() - t1.getTime()) / 1000.0));
        out.close();
	
		
	
    }
    static class FastScanner {

    private static BufferedReader reader;
    private static StringTokenizer tokenizer;


    public FastScanner(InputStream in) throws Exception {
        reader = new BufferedReader(new InputStreamReader(in));
        tokenizer = new StringTokenizer(reader.readLine().trim());
    }

    public int numTokens() throws Exception {
        if (!tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(reader.readLine().trim());
            return numTokens();
        }
        return tokenizer.countTokens();
    }

    public boolean hasNext() throws Exception {
        if (!tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(reader.readLine().trim());
            return hasNext();
        }
        return true;
    }

    public String next() throws Exception {
        if (!tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(reader.readLine().trim());
            return next();
        }
        return tokenizer.nextToken();
    }

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

    public float nextFloat() throws Exception {
        return Float.parseFloat(next());
    }

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

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

    public int[] nextIntArray() throws Exception {
        String[] line = reader.readLine().trim().split(" ");
        int[] out = new int[line.length];
        for (int i = 0; i < line.length; i++) {
            out[i] = Integer.valueOf(line[i]);
        }
        return out;
    }

    public double[] nextDoubleArray() throws Exception {
        String[] line = reader.readLine().trim().split(" ");
        double[] out = new double[line.length];
        for (int i = 0; i < line.length; i++) {
            out[i] = Double.valueOf(line[i]);
        }
        return out;
    }

    public Integer[] nextIntegerArray() throws Exception {
        String[] line = reader.readLine().trim().split(" ");
        Integer[] out = new Integer[line.length];
        for (int i = 0; i < line.length; i++) {
            out[i] = Integer.valueOf(line[i]);
        }
        return out;
    }

    public BigInteger[] nextBigIngtegerArray() throws Exception {
        String[] line = reader.readLine().trim().split(" ");
        BigInteger[] out = new BigInteger[line.length];
        for (int i = 0; i < line.length; i++) {
            out[i] = new BigInteger(line[i]);
        }
        return out;
    }

    public String nextLine() throws Exception {
        return reader.readLine().trim();
    }

    public BigInteger nextBigInteger() throws Exception {
        return new BigInteger(next());
    }
    }


   


    static class DEBUG {
        public static void DebugInfo(String disp) {
            System.err.println("DEBUG Info: " + disp);
        }

        public static void DebugVariable(String variable, String value) {
            System.err.println("DEBUG Info: " + variable + " => " + value);
        }


        public static void DebugVariable(String variable, int value) {
            System.err.println("DEBUG Info: " + variable + " => " + value);
        }


        public static void DebugVariable(String variable, long value) {
            System.err.println("DEBUG Info: " + variable + " => " + value);
        }

        public static void DebugArray(int[] value) {
            for (int i = 0; i < value.length; i++) {

                System.err.println("DEBUG Info: " + i + " => " + value[i]);
            }
        }

    }

}
