class Markdown {

String parse(String markdown) {

String[] lines = markdown.split("\n");

String result = "";

boolean activeList = false;

for (int i = 0; i < lines.length; i++) {

String theLine = parseHeader(lines[i]);

if (theLine == null) {

theLine = parseListItem(lines[i]);

}

if (theLine == null)

{

theLine = parseParagraph(lines[i]);

}

if (theLine.matches("(<li>).*") && !theLine.matches("(<h).*") && !theLine.matches("(<p>).*") && !activeList) {

activeList = true;

result = result + "<ul>";

result = result + theLine;

}

else if (!theLine.matches("(<li>).*") && activeList) {

activeList = false;

result = result + "</ul>";

result = result + theLine;

} else {

result = result + theLine;

}

}

if (activeList) {

result = result + "</ul>";

}

return result;

}

private String parseHeader(String markdown) {

int count = 0;

for (int i = 0; i < markdown.length() && markdown.charAt(i) == '#'; i++)

{

count++;

}

if (count > 6) { return "<p>" + markdown + "</p>"; }

if (count == 0) { return null; }

return "<h" + Integer.toString(count) + ">" + markdown.substring(count + 1) + "</h" + Integer.toString(count)+ ">";

}

private String parseListItem(String markdown) {

if (markdown.startsWith("*")) {

String skipAsterisk = markdown.substring(2);

String listItemString = parseSomeSymbols(skipAsterisk);

return "<li>" + listItemString + "</li>";

}

return null;

}

private String parseParagraph(String markdown) {

return "<p>" + parseSomeSymbols(markdown) + "</p>";

}

private String parseSomeSymbols(String markdown) {

String lookingFor = "__(.+)__";

String update = "<strong>$1</strong>";

String workingOn = markdown.replaceAll(lookingFor, update);

lookingFor = "_(.+)_";

update = "<em>$1</em>";

return workingOn.replaceAll(lookingFor, update);

}

}