Repeated String Hackerrank Solution in Java 

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'repeatedString' function below.
     *
     * The function is expected to return a LONG_INTEGER.
     * The function accepts following parameters:
     *  1. STRING s
     *  2. LONG_INTEGER n
     */

    public static long repeatedString(String s, long n) {
    // Write your code here
        long lengthOfStr=s.length();
        long remainder=n%lengthOfStr;
        long quotient=n/lengthOfStr;
        String remainString=s.substring(0,(int)remainder);
        int count=0;
        for(char ch:s.toCharArray()){
            if(ch=='a'){
               count++;
            }
        }
        long totalCount=count*quotient;
        for(char ch:remainString.toCharArray()){
            if(ch=='a')
            totalCount++;
        }
    
        return totalCount;
        
    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        String s = bufferedReader.readLine();

        long n = Long.parseLong(bufferedReader.readLine().trim());

        long result = Result.repeatedString(s, n);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}