import java.util.*;
import java.util.regex.*;
class Ideone
{
{
String s
= "**bold** _italic_ ~strike~ `**code**`"; String regex
= "(?s)`([^`]*)`|(\\*\\*|[_~])((?:(?!\\2).)*)\\2"; System.
out.
println(s.
replaceAll(regex,
"$1$3")); }
}
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