Exception in thread "main" java.util.UnknownFormatConversionExcept ion: Conversion = '%'

import com.teamtreehouse.model.Song;
import com.teamtreehouse.model.SongBook;

public class Karaoke {

  public static void main(String[] args) {
   Song song = new Song (
     "Michael Jackson",
     "Beat It",
     "https://www.youtube.com/watch?v=T2PAkPp0_bY");
    SongBook songBook = new SongBook();
    System.out.printf("Adding %s n%", song);
    songBook.addSong(song);
    System.out.printf("There are %d songs. %n", songBook.getSongCount());

  }
}

package com.teamtreehouse.model; //helpers classes

import java.util.ArrayList;
import java.util.List;

public class SongBook {
 private List<Song> mSongs;

 public SongBook() {
  mSongs = new ArrayList<Song>(); 
 }

 public void addSong(Song song) {
  mSongs.add(song); 
 }

 public int getSongCount() {
  return mSongs.size(); 
 }
}

package com.teamtreehouse.model;

public class Song {
 private String mArtist;
 private String mTitle;
 private String mVideoUrl;

 public Song (String artist, String title, String videoUrl) {
   mArtist = artist;
   mTitle = title;
   mVideoUrl = videoUrl;   
 }
  public String getTitle() {
   return mTitle; 
  }
  public String getArtist() {
   return mArtist; 
  }
  public String getVideoUrl() {
   return mVideoUrl; 
  }

  @Override
  public String toString() {
    return String.format("Song: %s by %s", mTitle, mArtist);
  }
}```