16 teams enter a competition. They are divided up into four Pools (A, B, C and D) of four teams each. Every team plays one match against the other teams in its pool.
After the Pool matches are completed:
the winner of Pool A plays the second placed team of Pool B
• the winner of Pool B plays the second placed team of Pool A
the winner of Pool C plays the second placed team of Pool D
• the winner of Pool D plays the second placed team of Pool C
The winners of these four matches then play semi-finals, and the winners of the semi-finals play in the final.
How many matches are played altogether?
63
32
23
31