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:
| Date | City | Opponent | Results¹ | Type of game |
| --- | --- | --- | --- | --- |
| January 16 | Cairo , Egypt | Egypt | 3:1 | Friendly |
| May 9 | Belgrade | Greece | 1:0 | 1954 WCQ |
| May 14 | Brussels , Belgium | Belgium | 3:1 | Friendly |
| May 21 | Belgrade | Wales | 5:2 | Friendly |
| June 5 | Zagreb | Turkey | 2:2 | Friendly |
| October 18 | Zagreb | France | 3:1 | Friendly |
| November 8 | Skoplje | Israel | 1:0 | 1954 WCQ |
Question:
On what date was there a friendly game against Wales?
Answer:
May 21