100 10
87 73
15 71
14 33
1 4
20 80
65 67
36 36
25 4
22 21
7 97
 4 2
3 3
3 4
 5 4
3 3
4 4
5 5
1 2
 4 4
1 2
2 3
3 1
4 4
 4 3
1 1
2 3
3 4
 1000000 1
255765 255765
 4 3
1 2
2 3
4 4
 4 2
1 1
1 2
 3 3
1 1
2 2
3 3
 5 4
1 1
2 3
2 4
2 5
 4 5
1 4
3 4
1 2
2 3
2 4
 4 4
2 3
2 4
3 4
4 4
 10 9
8 10
3 10
2 8
9 3
4 8
1 10
7 9
5 4
7 3
 10 10
1 2
2 3
3 4
4 5
5 1
6 6
7 7
8 8
9 9
10 10
 5 5
1 4
3 4
1 2
2 3
2 4
 3 3
1 2
2 2
3 3
 5 3
1 1
2 2
3 3
 6 12
1 2
1 3
2 3
1 1
2 2
3 3
4 5
5 6
4 6
4 4
5 5
6 6
 4 4
1 2
2 3
1 3
4 4
 5 4
1 2
3 3
4 4
5 5
 7 13
6 7
2 7
3 7
4 3
5 2
1 4
7 7
3 1
5 5
3 3
1 5
2 6
6 6
 2 2
1 1
2 2
 5 5
1 1
2 2
3 3
4 4
5 5
 1 1
1 1
 7 3
1 1
3 3
6 6
 3 3
1 1
2 3
3 3

0 1 0 0 0 0 0 1 0 0 8 6 12 0 8 0 0 0 0 0 57 0 0 0 0 0

import java.util.Scanner;


public class string {
public static void main(String[] args) {
    Scanner s = new Scanner(System.in);
    String input = s.next();
    int count = 0 ;
    String input2 = "";
    for( int i = 0 ; i < input.length();i++){
    if(input.charAt(i)=='a' || input.charAt(i)=='b'){
    input2 = input2 + input.charAt(i) ;
    } 
    }
   for(int k = 0 ; k<input2.length();k++){
   if(input2.charAt(0)=='a'){
   count = input2.length();
   }
   else{
   count = input2.length()-1;
   for(int n=0;n<input2.length();n++){
   if(input2.charAt(1)=='b'){
   count = input2.length()-2;
   for(int d=0;d<input2.length();d++){
   if(input2.charAt(2)=='b'){
   count = input2.length()-3;
   }
   
   }
   }
   }    
   
   }
   
   }
   System.out.print(count);
   }
      
   }
     