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:
| Rank | Nation | Gold | Silver | Bronze | Total |
| --- | --- | --- | --- | --- | --- |
| 1 | France | 28 | 28 | 24 | 80 |
| 2 | Romania | 16 | 3 | 5 | 24 |
| 3 | Canada | 14 | 10 | 15 | 39 |
| 4 | Quebec | 8 | 4 | 16 | 28 |
| 5 | Morocco | 6 | 11 | 7 | 24 |
| 6 | Tunisia | 4 | 7 | 1 | 12 |
| 7 | Egypt | 2 | 5 | 4 | 11 |
| 8 | Switzerland | 2 | 1 | 5 | 8 |
| 9 | Senegal | 2 | 1 | 3 | 6 |
| 10 | French Community of Belgium | 1 | 3 | 6 | 10 |
| 11 | Madagascar | 1 | 2 | 3 | 6 |
| 12 | Burkina Faso | 1 | - | 2 | 3 |
| 13 | Togo | 1 | - | 1 | 2 |
| 14 | Guinea | 1 | - | - | 1 |
| 15 | Lebanon | 1 | - | - | 1 |
| 16 | Ivory Coast | - | 3 | 3 | 6 |
| 17 | Republic of the Congo | - | 3 | 2 | 5 |
| 18 | New Brunswick | - | 1 | 2 | 3 |
| 19 | Central African Republic | - | 1 | - | 1 |
| 20 | Dominica | - | 1 | - | 1 |
| 21 | Gabon | - | 1 | - | 1 |
| 22 | Mali | - | 1 | - | 1 |
| 23 | Cambodia | - | - | 2 | 2 |
| 24 | Luxembourg | - | - | 2 | 2 |
| 25 | Mauritius | - | - | 2 | 2 |
| 26 | Burundi | - | - | 1 | 1 |
| 27 | Djibouti | - | - | 1 | 1 |
| 28 | Vietnam | - | - | 1 | 1 |
Question:
how many counties have at least one silver medal?
Answer:
18