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:
| Nationality | Name | Term as a Deputy Judge | Reason for termination |
| --- | --- | --- | --- |
| Norway | Frederik Beichmann | 30 January 1920 — 6 December 1930 | Not re-elected |
| China | Wang Ch'ung-hui | 30 January 1920 — 6 December 1930 | Not re-elected |
| Finland | Rafael Erich | 15 January 1931 — 1 February 1936 | Post abolished |
| Portugal | Jose Caeiro da Matta | 15 January 1931 — 1 February 1936 | Post abolished |
| Romania | Demetre Negulesco | 30 January 1920 — 6 December 1930 | Not re-elected |
| Yugoslavia | Mileta Novaković | 15 January 1931 — 1 February 1936 | Post abolished |
| Austria | Josef Redlich | 15 January 1931 — 1 February 1936 | Post abolished |
| Yugoslavia | Mihajlo Jovanović | 30 January 1920 — 6 December 1930 | Not re-elected |
Question:
how many judges served from january 15, 1931 to feb 1, 1936?
Answer:
4