Problem: One day Nikita found the string containing letters "a" and "b" only. 

Nikita thinks that string is beautiful if it can be cut into 3 strings (possibly empty) without changing the order of the letters, where the 1-st and the 3-rd one contain only letters "a" and the 2-nd contains only letters "b".

Nikita wants to make the string beautiful by removing some (possibly none) of its characters, but without changing their order. What is the maximum length of the string he can get?

Input

The first line contains a non-empty string of length not greater than 5 000 containing only lowercase English letters "a" and "b". 

Output

Print a single integer — the maximum possible size of beautiful string Nikita can get.

Examples

Input

abba


Output

4

Input

bab


Output

2

Note

It the first sample the string is already beautiful.

In the second sample he needs to delete one of "b" to make it beautiful.

Solution (in JAVA):

Solution:
/* 
 * UMANG PANCHAL
 * DAIICT
 */
import java.util.*;
import java.io.*;
import java.math.BigInteger;
public class Main
{
 
	static ArrayList<Integer> adj[];
	static char color[];
	static boolean b[],visited[],possible;
	static int level[];
	static Map<Integer,HashSet<Integer>> s;
	static int totalnodes,colored;
	static int count[];
	static long sum[];
	static int nodes;
	static double ans=0;
	static long[] as=new long[10001];
	static long c1=0,c2=0;
	static int[] a,d,k;
	static int max=100000000;
	static long MOD = (long)1e9 + 7,sm=0,m=Long.MIN_VALUE;
	static boolean[] prime=new boolean[1000005];
	
	// --------------------My Code Starts Here----------------------
	
	public static void main(String[] args) throws IOException
	{
		in=new InputReader(System.in);
		w=new PrintWriter(System.out);
      String s=ns();
      int n=s.length();
      char[] c=s.toCharArray();
      int[] pa=new int[n+2];
      int[] pb=new int[n+2];
      pa[0]=0;
      pb[0]=0;
      for(int i=0;i<n;i++)
      {
    		  if(c[i]=='a')
    		  {
    			  pa[i+1]=pa[i]+1;
    			  pb[i+1]=pb[i];
    		  }
    		  else
    		  {
    			  pa[i+1]=pa[i];
    			  pb[i+1]=pb[i]+1;
    		  }
    	  
      }
      pa[n+1]=pa[n];
      pb[n+1]=pb[n];
      int max=0;
      for(int i=0;i<=n+1;i++)
         for(int j=i;j<=n+1;j++)
        	 max=Math.max(max,pa[i]+pb[j]-pb[i]+pa[n+1]-pa[j]);
    
    	 w.print(max); 
    	  w.close();
    }

	public static boolean isPrime(int n)
	{
	    // Corner cases
	    if (n <= 1)  return false;
	    if (n <= 3)  return true;
	 
	    // This is checked so that we can skip 
	    // middle five numbers in below loop
	    if (n%2 == 0 || n%3 == 0)
	    	return false;
	 
	    for (int i=5; i*i<=n; i=i+6)
	        if (n%i == 0 || n%(i+2) == 0)
	           return false;
	 
	    return true;
	}
	
	// --------------------My Code Ends Here------------------------
	
	public static String ns()
	{
		return in.nextLine();
	}
	public static int ni()
	{
		return in.nextInt();
	}
	public static long nl()
	{
		return in.nextLong();
	}
	public static int[] na(int n)
	{
		a=new int[n];
		for(int i=0;i<n;i++)
		a[i]=ni();
		return a;
	}
	public static void sieveOfEratosthenes()
	    {
	       int n=prime.length;
	        for(int i=0;i<n;i++)
	            prime[i] = true;
	         
	        for(int p = 2; p*p <=n; p++)
	        {
	            if(prime[p] == true)
	            {
	                for(int i = p*2; i <n; i += p)
	                    prime[i] = false;
	            }
	        }
	    }

	public static boolean printDivisors(long n)
    {
		long ans=0;
        for (int i=1; i<=Math.sqrt(n); i++)
        {
            if (n%i==0)
            {
                if (n/i == i)
                    ans++;
                else 
                {
                	ans=ans+2;
                }
            }
            if(ans>3)
            	break;
        }
        if(ans==3)
        	return true;
        else
        	return false;
    }

  public static void dfs(int i)
  {
	  visited[i]=true;
	  for(int j:adj[i])
	  {
		  if(!visited[j])
			  {
			  dfs(j);
			  nodes++;
			  }
	  }
	  
  }
  public static String rev(String s)
	{
		StringBuilder sb=new StringBuilder(s);
		sb.reverse();
		return sb.toString();
	}
	static long lcm(long a, long b)
	{
	    return a * (b / gcd(a, b));
	}
	static long gcd(long a, long b)
	{
	    while (b > 0)
	    {
	        long temp = b;
	        b = a % b; // % is remainder
	        a = temp;
	    }
	    return a;
	}
	static InputReader in;
	static PrintWriter w;
static class InputReader 
{
 
private final InputStream stream;
private final byte[] buf = new byte[8192];
private int curChar, snumChars;
private SpaceCharFilter filter;
 
public InputReader(InputStream stream)
{
  this.stream = stream;
}
 
public int snext()
{
  if (snumChars == -1)
    throw new InputMismatchException();
  if (curChar >= snumChars)
  {
    curChar = 0;
    try 
    {
      snumChars = stream.read(buf);
    }
    catch (IOException e)
    {
      throw new InputMismatchException();
    }
    if (snumChars <= 0)
      return -1;
  }
  return buf[curChar++];
}
 
public int nextInt() 
{
  int c = snext();
  while (isSpaceChar(c)) 
  {
    c = snext();
  }
  int sgn = 1;
  if (c == '-')
  {
    sgn = -1;
    c = snext();
  }
  int res = 0;
  do
  {
    if (c < '0' || c > '9')
      throw new InputMismatchException();
    res *= 10;
    res += c - '0';
    c = snext();
  }
  while (!isSpaceChar(c));
  return res * sgn;
}
 
public long nextLong() 
{
  int c = snext();
  while (isSpaceChar(c)) 
  {
    c = snext();
  }
  int sgn = 1;
  if (c == '-')
  {
    sgn = -1;
    c = snext();
  }
  long res = 0;
  do
  {
    if (c < '0' || c > '9')
      throw new InputMismatchException();
    res *= 10;
    res += c - '0';
    c = snext();
  }
  while (!isSpaceChar(c));
  return res * sgn;
}	    
public String readString() 
{
  int c = snext();
  while (isSpaceChar(c)) 
  {
    c = snext();
  }
  StringBuilder res = new StringBuilder();
  do
  {
    res.appendCodePoint(c);
    c = snext();
  }
  while (!isSpaceChar(c));
  return res.toString();
}
 
public String nextLine() 
{
  int c = snext();
  while (isSpaceChar(c))
    c = snext();
  StringBuilder res = new StringBuilder();
  do
  {
    res.appendCodePoint(c);
    c = snext();
  }
  while (!isEndOfLine(c));
  return res.toString();
}
 
public boolean isSpaceChar(int c)
{
  if (filter != null)
    return filter.isSpaceChar(c);
  return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
}
 
private boolean isEndOfLine(int c) 
{
  return c == '\n' || c == '\r' || c == -1;
}
 
public interface SpaceCharFilter
{
  public boolean isSpaceChar(int ch);
}
}
	
}