Repeated String - HackerRank

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class Repeated_String {

        public static void main(String[] args) throws IOException{
            
            long result = 0;
            
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            String str = br.readLine();
            Long cnt = Long.parseLong(br.readLine());
            int strLeng = str.length();
            br.close();
            
            char[] sArr = str.toCharArray();
            int[] aCnt = new int[strLeng];
            for(int i = 0 ; i < strLeng ; i++){
                if(sArr[i] == 'a'){
                    if(i != 0){
                    aCnt[i] = aCnt[i-1] +1;
                    } else {
                        aCnt[i] = 1;
                    }
                } else{
                    if(i != 0){
                        aCnt[i] = aCnt[i-1];
                    } else{
                        aCnt[i] = 0;
                    }
                }
            }
            
            
            result = cnt / strLeng * aCnt[strLeng-1];    
            
            if(cnt % strLeng != 0){
                result += aCnt[(int)(cnt % strLeng-1)];
            }
            
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
            bw.write(String.valueOf(result));
            bw.flush();
            bw.close();
            
        }
}