import java.io.*;
public class Test {
public static void main(String[] args) throws IOException {
//estimateTime is a variable of type long
long estimateTime = 250L;
//append execution time to file
BufferedWriter w = new BufferedWriter(new FileWriter("abc.txt", true));
w.write((int)'a');
w.newLine();
String s = String.valueOf(estimateTime);
w.write(s, 0, s.length());
w.newLine();
s = Long.toString(estimateTime);
w.write(s, 0, s.length());
w.close();
}
}