Answer
62,994,022,035,644,700 ways to select 12 countries as a council
Work Step by Step
Ways to select 3 from 45 = $C$(45,3) = 14190
Ways to select 4 from 57 = $C$(57,4) = 395010
Remaining countries = 12 - (3 + 4) = 5
Ways to select 5 from 69 = $C$(69,5) = 11238513
Using product rule ,
Ways to select 12 countries = 14190$\times$395010$\times$11238513 = 62,994,022,035,644,700