import java.util.*
 
fun main(args: Array<String>) {
    fun maskEmail(email: String): String {
	    return email.replace(Regex("""((?:\.|^).)?.(?=.*@)"""), "$1*")
	}
	
	val emails = arrayOf<String>("captain.am-e-r-ica@email.com","my-cutie.pie+here@email.com","tom.cat@email.com","cutie.pie@email.com","captain.america@email.com")
    for(email in emails) {    
      val masked = maskEmail(email)
      println("${email}: ${masked}")    
    }
}