BIT is not showing the correct value

I am having a String , i am creating a BIT of String based on the frequency of the element present String:

abcdbcaab

Code:

class Test{
static int[][] dp;

    public static void update(int i , int val ,int[] dpp){

         while(i<=100000){

             dpp[i]+=val;
             i+= (i&-i);
         }


    }

    public static int value(int i ,int[] dp){

         int ans =0;

         while(i>0){
             ans+=dp[i];
             i-= (i&i);
         }
         return ans;
    }


    public static void main(String args[] ) throws IOException {

    Scanner in = new Scanner(new InputStreamReader(System.in));

    dp = new int[27][1000001];
    String s  = in.next();
    for(int i=0;i<s.length();i++){
        update(i+1,1,dp[s.charAt(i)-'a']);

    }
    System.out.println(dp[0][7]); // Should show 2 as the frequency of 'a' at 7 position is 2
    }
    }

Where i am doing wrong . i could not get it but dp[0][8] is showing me 3

Please Help i could not figure it out where i have commit mistake