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.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.StringTokenizer;

public class magic2 {
	public static void main(String[] args) throws Exception {
		FasterScanner sc = new FasterScanner();
		PrintWriter out = new PrintWriter(System.out);
		long N = sc.nextLong();
		long found = 0;
		HashSet<Long> HS = new HashSet<Long>();
		for(int masksize=1;masksize<=10;masksize++){
			for(int mask=0;mask<(1<<masksize);mask++){
				for(int x=0;x<=9;x++){
					for(int y=x+1;y<=9;y++){
						//zeros are x
						//ones are y
						StringBuilder temp = new StringBuilder();
						for(int a=0;a<masksize;a++){
							if(((mask>>a)&1)==0){
								temp.append(x);
							}
							else temp.append(y);
						}
						if(temp.charAt(0)=='0')continue;
						long num = Long.parseLong(temp.toString());
						if(num<=N)HS.add(num);
					}
				}
			}
		}
		
		out.println(HS.size());
		out.close();
	}


	static class FasterScanner{
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;
		
		public FasterScanner(){
			stream = System.in;
		}
		int read(){
			if(numChars==-1)
				throw new InputMismatchException();
			if(curChar>=numChars){
				curChar = 0;
				try{
					numChars = stream.read(buf);
				} catch (IOException e){
					throw new InputMismatchException();
				}
				if(numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
		
		boolean isSpaceChar(int c){
			return c==' '||c=='\n'||c=='\r'||c=='\t'||c==-1;
		}
		boolean isEndline(int c){
			return c=='\n'||c=='\r'||c==-1;
		}
		int nextInt(){
			return Integer.parseInt(next());
		}
		long nextLong(){
			return Long.parseLong(next());
		}
		double nextDouble(){
			return Double.parseDouble(next());
		}
		String next(){
			int c = read();
			while(isSpaceChar(c))
				c=read();
			StringBuilder res = new StringBuilder();
			do{
				res.appendCodePoint(c);
				c=read();
			} while(!isSpaceChar(c));
			return res.toString();
		}
		String nextLine(){
			int c = read();
			while(isEndline(c))
				c=read();
			StringBuilder res = new StringBuilder();
			do{
				res.appendCodePoint(c);
				c = read();
			}while(!isEndline(c));
			return res.toString();
		}
		
	}
	static class FastScanner {
		BufferedReader br;
		StringTokenizer st;

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

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

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

		public String next() throws Exception {
			if (!st.hasMoreTokens()) {
				st = new StringTokenizer(br.readLine().trim());
				return next();
			}
			return st.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 String nextLine() throws Exception {
			return br.readLine();
		}
	}

}
