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 | Single | Charts\nFR | Charts\nBEL\nWa | Charts\nSWI | Certification | Album |
| --- | --- | --- | --- | --- | --- | --- |
| 1997 | "Sur la route" | 14 | — | — |  | La dernière année |
| 2000 | "J'en rêve encore" | 7 | 4 | — |  | Marcher dans le sable |
| 2001 | "Une seule vie (marcher dans le sable)" | 30 | — | — |  | Marcher dans le sable |
| 2001 | "Tomber" | 35 | — | — |  | Marcher dans le sable |
| 2004 | "Elle s'ennuie" | 35 | — | 73 |  |  |
| 2004 | "Elle danse seule" | 22 | — | 46 |  | Un homme sans racines |
| 2011 | "L'étranger" | 59 | — | — |  | Sur ma route |
| 2013 | "Je me souviens de tout" | 130 | — | — |  | Da Palmas |
Question:
how many songs were not listed on the swiss charts?
Answer:
6