Little Eugene

Little Eugene has bought a new juicer recently. Every morning his brothers, sisters and he drink fresh juice. And it, by the way, is very healthy. They understood, that they can drink juice made not just from one kind of fruits, for example orange, but also some mixes, like grape-apple. Everybody likes juice in Little Eugene's family, so they can drink more then one cup of different types of juice at morning. Little Eugene, as the most smart, makes juice for his family every morning. Lets describe the process of making juice: Little Eugene puts fruits into the juicer, mix them and collect juice into some container. The main problem is that sometimes this container have to be washed. For example, if he will make an apple juice after he made orange one, he'll get an apple-orange juice, instead of clear apple. More formally, let juice A contains from components a1,a2,a3..an and juice B - from b1,b2,b3..bm. We can make juice B after juice A only if B contains all the components of A (for every i there is at least one j that bj equal to ai). Otherwise container has to be washed before making juice B. Little Eugene do not like to wash container, so he wants to do it least possible number of times.
Help him to find the order of making juice.