Complex sentence: In all, Yugoslavia did not participate in 5 contests: from 1977 to 1980 and again in 1985, due to national memorial day for 5 years of anniversary of death of marshal Tito being held in the country.
Split into simpler sentences: In all, Yugoslavia did not participate in 5 contests, from 1977 to 1980. Yugoslavia withdrew again in 1985, due to national memorial day for 5 years of anniversary of death of marshal Tito being held in the country.