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 |
| --- | --- | --- | --- | --- |
| April 6 | Marseille , France | France | 1:1 | Euro '68 Qualifying |
| April 24 | Belgrade | France | 4:1 | Euro '68 Qualifying |
| April 27 | Belgrade | Czechoslovakia | 0:3 | Friendly |
| June 5 | Florence , Italy | England | 1:0 | Euro '68 Semi-Finals |
| June 8 | Rome, Italy | Italy | 1:1 | Euro '68 Finals |
| June 10 | Rome, Italy | Italy | 0:2 | Euro '68 Finals (Replay) |
| June 25 | Split | Brazil | 0:2 | Friendly |
| September 25 | Belgrade | Finland | 9:1 | 1970 WCQ |
| October 16 | Bruxelles , Belgium | Belgium | 0:3 | 1970 WCQ |
| October 27 | Belgrade | Spain | 0:0 | 1970 WCQ |
| December 17 | Rio de Janeiro , Brazil | Brazil | 3:3 | Friendly |
| December 19 | Belo Horizonte , Brazil | Brazil | 2:3 | Friendly |
| December 22 | Mar del Plata , Argentina | Argentina | 1:1 | Friendly |
Question:
What type of game was held on December 22?
Answer:
Friendly