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.
///package TreeDfs;
import java.io.*;
import java.util.*;
/**
 *
 * @author prabhat
 */
public class dfs1 {

    //static int[] a;
    static int[] S;
    static long[] sum;
   public static int mod=1000000007;
   static int[][] dp;
   static boolean[][] isPalin;
   static int max1=5000+10;
   static int[][] g;
   static int ver;
   static int n,k,m;
   static boolean[] visit;
   static LinkedList<Pair> l[];
   static int ans=0;
   static int[] color,log,st[],a[],prefixSum[];
  
  public static void main(String[] args) throws Exception
   {
   	InputReader in = new InputReader(System.in);
   	PrintWriter pw=new PrintWriter(System.out);
     
        int n=in.ii();
        TreeSet<Integer> ts=new TreeSet<>();
        
        for(int d1=0;d1<9;d1++)
        {
            for(int d2=d1+1;d2<=9;d2++)
            {
                for(int len=1;len<10;len++)
                {
                    for(int mask=0;mask<(1<<len);mask++)
                    {
                        
                        int x=0;
                        for(int i=0;i<len;i++)
                        {
                            x*=10;
                            if((mask&(1<<i))>0)
                                x+=d1;
                            else x+=d2;
                        }
                        if(x<=n&&x>0)
                           ts.add(x);
                    }
                    
                }
                
            }
        }
        if(1000000000<=n)ts.add(1000000000);
        pw.println(ts.size());
        
        
        
   	 pw.close();
   }
  static int getSum(int x1,int y1,int x2,int y2)
  {
      int total=prefixSum[x2][y2];
      int n=y1>0?prefixSum[x2][y1-1]:0;
      int w=x1>0?prefixSum[x1-1][y2]:0;
      int nw=x1>0&&y1>0?prefixSum[x1-1][y1-1]:0;
      return total-n-w+nw;
  }
   static class SparseTable2D  
   {
	int sparse[][][][];
	int log[];
	int R,C;
 
	int getMax(int x1,int y1,int x2,int y2, boolean build){
	    int x_sz = x2 - x1 + 1;
	    int y_sz = y2 - y1 + 1;
	    int k1 = (x_sz == 1) ? 0 :log[build ? (x_sz - 1) : x_sz];
	    int k2 = (y_sz == 1) ? 0 :log[build ? (y_sz - 1) : y_sz];
	    int NW = sparse[k1][k2][x1][y1]; 					   //North-West
	    int NE = sparse[k1][k2][x1][y2 - (1 << k2) + 1];    		   //North-East
	    int SW = sparse[k1][k2][x2 - (1 << k1) + 1][y1]; 		           //South-West
	    int SE = sparse[k1][k2][x2 - (1 << k1) + 1][y2 - (1 << k2) + 1];       //South-East
	    return (int) Math.max(Math.max(NW,NE),Math.max(SW,SE));
	}
 
	SparseTable2D(int arr[][],int R,int C)
	{
	    this.R = R;
	    this.C = C;
	    
	    log = new int[Math.max(R,C) + 1000];
	    for(int i=2;i<log.length;i++)		
		log[i] = ((i & (i-1)) == 0) ? log[i-1] + 1 : log[i-1];
	    
	    int k1 = log[R] + 1;
	    int k2 = log[C] + 1;
	    sparse = new int[k1][k2][R][C];
	    for(int i=0;i<R;i++)
		for(int j=0;j<C;j++)
		    sparse[0][0][i][j] = arr[i][j];
 
	    for(int h=0;h<k1;h++)
	    {
		for(int v=0;v<k2;v++)
		{
		    if(!(h == 0 && v == 0))
		    {
			for(int i=0;i+(1<<h) <= R;i++)
			{
			    for(int j=0;j+(1<<v) <= C;j++)
			    {
				sparse[h][v][i][j] = getMax(i, j, i + (1<<h) - 1, j + (1<<v) - 1, true);
			    }
			}
		    }
		}
	    }
 
	}
    }
 static class SparseTable1D
    {
	int sparse[][];
	int len;
	int log[];
	SparseTable1D(int arr[])
	{
	    len = arr.length;
	    log = new int[len + 1000];
	    for(int i=2;i<log.length;i++)		
		log[i] = ((i & (i-1)) == 0) ? log[i-1] + 1 : log[i-1];
	    
	    int k = log[len] + 1;	    
	    sparse = new int[len][k];
	    for(int i=0;i<len;i++)
		sparse[i][0] = arr[i];
 
	    for(int j=1;j<k;j++)
	    {
		for(int i=0;i+(1<<j) <= len;i++)
		{
		    sparse[i][j] = Math.max(sparse[i][j-1],sparse[i+(1<<(j-1))][j-1]);
		}
	    }
	}
 
	int getMaxInRange(int L,int R)
	{
	    int sz = R - L + 1;
	    int k  = log[sz];
	    int v1 = sparse[L][k];
	    int v2 = sparse[R-(1<<k)+1][k];
	    return Math.max(v1,v2);
	}
 
    }
  private static class DSU{
		int[] parent;
		int[] rank;
		int cnt;
		public DSU(int n){
			parent=new int[n];
			rank=new int[n];
			for(int i=0;i<n;i++){
				parent[i]=i;
				rank[i]=1;
			}
			cnt=n;
		}
		int find(int i){
	        while(parent[i] !=i){
	        	parent[i]=parent[parent[i]];
	        	i=parent[i];
	        }
	        return i;
	    }
		int Union(int x, int y){
	        int xset = find(x);
	        int yset = find(y);
	        if(xset!=yset)
	        	cnt--;
	        if(rank[xset]<rank[yset]){
	        	parent[xset] = yset;
		        rank[yset]+=rank[xset];
		        rank[xset]=0;
		        return yset;
	        }else{
	        	parent[yset]=xset;
	        	rank[xset]+=rank[yset];
	        	rank[yset]=0;
	        	return xset;
	        }
	    }
	}
  public static int[][] packU(int n, int[] from, int[] to, int max) {
	    
	    int[][] g = new int[n][];
	    int[] p = new int[n];
	    for (int i = 0; i < max; i++) p[from[i]]++;
	    for (int i = 0; i < max; i++) p[to[i]]++;
	    for (int i = 0; i < n; i++) g[i] = new int[p[i]];
	    for (int i = 0; i < max; i++) {
	        g[from[i]][--p[from[i]]] = to[i];
	        g[to[i]][--p[to[i]]] = from[i];
	    }
	    return g;
	}
	public static int[][] parents3(int[][] g, int root) {
	    int n = g.length;
	    int[] par = new int[n];
	    Arrays.fill(par, -1);
 
	    int[] depth = new int[n];
	    depth[0] = 0;
 
	    int[] q = new int[n];
	    q[0] = root;
	    for (int p = 0, r = 1; p < r; p++) {
	        int cur = q[p];
	        for (int nex : g[cur]) {
	            if (par[cur] != nex) {
	                q[r++] = nex;
	                par[nex] = cur;
	                depth[nex] = depth[cur] + 1;
	            }
	        }
	    }
	    return new int[][]{par, q, depth};
	}
	public static int lower_bound(int[] nums, int target) {
        int low = 0, high = nums.length - 1;
        while (low < high) {
            int mid = low + (high - low) / 2;
            if (nums[mid] < target)
                low = mid + 1;
            else
                high = mid;
        }
        return nums[low] == target ? low : -1;
    }
 
    public static int upper_bound(int[] nums, int target) {
        int low = 0, high = nums.length - 1;
        while (low < high) {
            int mid = low + (high + 1 - low) / 2;
            if (nums[mid] > target)
                high = mid - 1;
            else
                low = mid;
        }
        return nums[low] == target ? low : -1;
    }
  public static boolean palin(String s)
	{
	   int i=0;
	   int j=s.length()-1;
	   while(i<j)
	   {
		   if(s.charAt(i)==s.charAt(j))
		   {
			   i++;
			   j--;
		   }
		   else return false;     
	   }
	   return true;
	}
	
    static boolean CountPs(String s,int n)
       {
    	boolean b=false;
    	     char[] S=s.toCharArray();
	       int[][] dp=new int[n][n];
	       boolean[][] p=new boolean[n][n];
	       for(int i=0;i<n;i++)p[i][i]=true;
	     
	       for(int i=0;i<n-1;i++)
	       {
	    	   if(S[i]==S[i+1])
	    	   {
	    		p[i][i+1]=true;
	    		dp[i][i+1]=1;
	    		b=true;
	    	   }
	       }
	    
	       for(int gap=2;gap<n;gap++)
	       {
	    	   for(int i=0;i<n-gap;i++)
	    	   {
	    		   int j=gap+i;
	    		   if(S[i]==S[j]&&p[i+1][j-1]){p[i][j]=true;}
	    		  
	    		  if(p[i][j])
	    			   dp[i][j]=dp[i][j-1]+dp[i+1][j]+1-dp[i+1][j-1];
	    		   
	    		   else  dp[i][j]=dp[i][j-1]+dp[i+1][j]-dp[i+1][j-1];
	    		  
	    		   if(dp[i][j]>=1){b=true;}
	    	   }
	       }
	      
	    return b; 
   // return dp[0][n-1];
	       
    }
  
  
  
 
 
public static int gcd(int a,int b)
{
	int res=1;
	while(a>0)
	{
		res=a;
		a=b%a;
		b=res;
	}
	return res;
}
 
 
public static long pow(long n,long p,long m)
{
	 long  result = 1;
	  if(p==0)
	    return 1;
	if (p==1)
	    return n;
	while(p!=0)
	{
	    if(p%2==1)
	        result *= n;
	    if(result>=m)
	    result%=m;
	    p >>=1;
	    n*=n;
	    if(n>=m)
	    n%=m;
	}
	return result;
}
public static long pow(long n,long p)
{
	long  result = 1;
	  if(p==0)
	    return 1;
	if (p==1)
	    return n;
	while(p!=0)
	{
	    if(p%2==1)
	        result *= n;
	    p >>=1;
	    n*=n;
	}
	return result;
 
}
 
 
 
 
static class Edge implements Comparator<Edge> {
	private int u;
	private int v;
	private int w;
	public Edge() {
	}
	public Edge(int u, int v, int w) {
		this.u=u;
		this.v=v;
		this.w=w;
	}
	public int getU() {
		return u;
	}
	public void setU(int u) {
		this.u = u;
	}
	public int getV() {
		return v;
	}
	public void setV(int v) {
		this.v = v;
	}
	public int getW() {
		return w;
	}
	public void setW(int w) {
		this.w = w;
	      }
	public int compareTo(Edge e)
	  {
		return this.getW() - e.getW();
	}
	@Override
	public String toString() {
		return "Edge [u=" + u + ", v=" + v + ", w=" + w + "]";
	}
	@Override
	public int compare(Edge arg0, Edge arg1) {
		// TODO Auto-generated method stub
		return 0;
	}
}
 
 
 
static class Pair implements Comparable<Pair>
{
	int a,b;
	Pair (int a,int b)
	{
		this.a=a;
		this.b=b;
	}
 
        @Override
        public int compareTo(Pair o) {
            //throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
          
           return this.b-o.b;
        }
 
}
 
static  class InputReader
{
   private InputStream stream;
   private byte[] buf = new byte[1024];
 
   private SpaceCharFilter filter;
    byte inbuffer[] = new byte[1024];
   int lenbuffer = 0, ptrbuffer = 0;
    final int M = (int) 1e9 + 7;
   int md=(int)(1e7+1);
    int[] SMP=new int[md];
   final double eps = 1e-6;
   final double pi = Math.PI;
 
	PrintWriter out;
   String check = "";
 InputStream   obj = check.isEmpty() ? System.in : new ByteArrayInputStream(check.getBytes());
   public InputReader(InputStream stream)
   {
       this.stream = stream;
   }
 
    int readByte() {
	        if (lenbuffer == -1) throw new InputMismatchException();
	        if (ptrbuffer >= lenbuffer) {
	            ptrbuffer = 0;
	            try {
	                lenbuffer = obj.read(inbuffer);
	            } catch (IOException e) {
	                throw new InputMismatchException();
	            }
	        }
	        if (lenbuffer <= 0) return -1;
	        return inbuffer[ptrbuffer++];
   }
 
   public  int read()
   {
       int c = read();
       while (isSpaceChar(c))
           c = read();
       int sgn = 1;
       if (c == '-')
       {
           sgn = -1;
           c = read();
       }
       int res = 0;
       do
       {
           if (c < '0' || c > '9')
               throw new InputMismatchException();
           res *= 10;
           res += c - '0';
           c = read();
       } while (!isSpaceChar(c));
       return res * sgn;
   }
 
   String is() {
	        int b = skip();
	        StringBuilder sb = new StringBuilder();
	        while (!(isSpaceChar(b))) // when nextLine, (isSpaceChar(b) && b!=' ')
	        {
	            sb.appendCodePoint(b);
	            b = readByte();
	        }
	        return sb.toString();
   }
   public   int ii() {
	        int num = 0, b;
	        boolean minus = false;
	        while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')) ;
	        if (b == '-') {
	            minus = true;
	            b = readByte();
	        }
	        while (true) {
	            if (b >= '0' && b <= '9') {
	                num = num * 10 + (b - '0');
	            } else {
	                return minus ? -num : num;
	            }
	            b = readByte();
	        }
   }
 public   long il() {
	        long num = 0;
	        int b;
	        boolean minus = false;
	        while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')) ;
	        if (b == '-') {
	            minus = true;
	            b = readByte();
	        }
	        while (true) {
	            if (b >= '0' && b <= '9') {
	                num = num * 10 + (b - '0');
	            } else {
	                return minus ? -num : num;
	            }
	            b = readByte();
	        }
   }
   
	    boolean isSpaceChar(int c) {
	        return (!(c >= 33 && c <= 126));
	       }
 
	      int skip()
	        {
	        int b;
	        while ((b = readByte()) != -1 && isSpaceChar(b)) ;
	        return b;
	        }
 
	    float nf() {
	        return Float.parseFloat(is());
	    }
 
	    double id() {
	        return Double.parseDouble(is());
	    }
 
	    char ic() {
	        return (char) skip();
	    }
 
	    int[] iia(int n) {
	        int a[] = new int[n];
	        for (int i = 0; i<n; i++) a[i] = ii();
	        return a;
	    }
 
	    long[] ila(int n) {
	        long a[] = new long[n];
	        for (int i = 0; i <n; i++) a[i] = il();
	        return a;
	    }
 
	    String[] isa(int n) {
	        String a[] = new String[n];
	        for (int i = 0; i < n; i++) a[i] = is();
	        return a;
	    }
 
 
		 long mul(long a, long b) { return a * b % M; }
 
			long div(long a, long b)
				 {
					return mul(a, pow(b, M - 2));
 
		           }
 
 
 
	    double[][] idm(int n, int m) {
	        double a[][] = new double[n][m];
	        for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) a[i][j] = id();
	        return a;
	        }
 
	    int[][] iim(int n, int m) {
	        int a[][] = new int[n][m];
	        for (int i = 0; i < n; i++) for (int j = 0; j <m; j++) a[i][j] = ii();
	        return a;
          }
 
 
   public String readLine() {
       int c = read();
       while (isSpaceChar(c))
           c = read();
       StringBuilder res = new StringBuilder();
       do {
           res.appendCodePoint(c);
           c = read();
       } while (!isEndOfLine(c));
       return res.toString();
   }
 
   public interface SpaceCharFilter
   {
       public boolean isSpaceChar(int ch);
   }
   public boolean isEndOfLine(int c) {
       return c == '\n' || c == '\r' || c == -1;
   }
}
 
}
  