Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year | Competition | Venue | Position | Event | Notes |
| --- | --- | --- | --- | --- | --- |
| 1994 | European Championships | Helsinki, Finland | 48th | Marathon | 2:22:49 |
| 1995 | World Championships | Gothenburg, Sweden | 49th | Marathon | 2:33:42 |
| 1996 | Summer Olympics | Atlanta, Georgia | 58th | Marathon | 2:23:14 |
| 1997 | World Championships | Athens, Greece | 48th | Marathon | 2:29:10 |
| 1998 | World Cross Country Championships | Marrakech, Morocco | 85th | Long race |  |
| 1998 | World Half Marathon Championships | Uster, Switzerland | 66th | Half marathon | 1:05:00 |
| 1998 | European Championships | Budapest, Hungary | 29th | Marathon | 2:19:38 |
| 1999 | World Half Marathon Championships | Palermo, Italy | 55th | Half marathon | 1:05:45 |
| 1999 | Frankfurt Marathon | Frankfurt, Germany | 1st | Marathon | 2:12:37 |
| 1999 | Helsinki Marathon | Helsinki, Finland | 1st | Marathon | 2:19:18 |
| 2000 | Summer Olympics | Sydney, Australia | 35th | Marathon | 2:19:41 |
| 2001 | Frankfurt Marathon | Frankfurt, Germany | 1st | Marathon | 2:11:09 |
| 2002 | Paris Marathon | Paris, France | 2nd | Marathon | 2:08:53 |
| 2002 | European Championships | Munich, Germany | 2nd | Marathon | 2:13:18 |
| 2002 | Fukuoka Marathon | Fukuoka, Japan | 4th | Marathon | 2:10:14 |
| 2003 | JoongAng Seoul Marathon | Seoul, South Korea | 1st | Marathon | 2:09:15 |
| 2004 | Summer Olympics | Athens, Greece | 26th | Marathon | 2:18:09 |
| 2004 | JoongAng Seoul Marathon | Seoul, South Korea | 1st | Marathon | 2:09:34 |
| 2005 | JoongAng Seoul Marathon | Seoul, South Korea | 4th | Marathon | 2:12:12 |
| 2006 | Paris Marathon | Paris, France | 12th | Marathon | 2:11:25 |
| 2007 | World Championships | Osaka, Japan | — | Marathon | DNF |
| 2007 | Beppu-Ōita Marathon | Beppu-Ōita, Japan | 8th | Marathon | 2:14:49 |
| 2008 | Summer Olympics | Beijing, China | 75th | Marathon | 2:39:01 |
Question:
which four competitions are the only competitions that occurred once?
Answer:
World Cross Country Championships, Helsinki Marathon, Fukuoka Marathon, Beppu-Ōita Marathon