4. Each of the 10 dwarfs either always tells the truth or always lies. It is known that each of them loves exactly one type of ice cream: butter, chocolate, or fruit. First, Snow White asked those who love butter ice cream to raise their hands, and everyone raised their hands, then those who love chocolate ice cream - and half of the dwarfs raised their hands, then those who love fruit ice cream - and only one dwarf raised their hand. How many of the dwarfs are truthful?