Conversation so far:
who won the very first fifa world cup
Uruguay defeated Argentina 4 to 2 and became the first nation to win the FIFA World Cup.
who qualified for semi finals at the first fifa world cup
Argentina, Uruguay, the United States and Yugoslavia each won their respective groups to qualify for the semi-finals for the 1930 FIFA World Cup.

Question: how many teams participated in the event
Self-contained rewrite: how many teams participated in the first fifa world cup