Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

Input: Consider Input: pablo escobar and his brother's school once sent them home because they had no shoes and no money to buy them.

Output: pablo escobar


Input: Consider Input: the british rail class 931 was reserved for former southern region electrical multiple units converted for departmental use.

Output: british rail class 931


Input: Consider Input: the palaeoptera is the group of primitive (basal) winged insects which do not fold the wings back over the abdomen, as neoptera do.


Output: palaeoptera