A labeled tree is a tree where each vertex is assigned a label. Two labeled trees are considered isomorphic when there is an isomorphism between them that preserves the labels of vertices. How many nonisomorphic trees are there with three vertices labeled with different integers from the set {1, 2, 3}? How many nonisomorphic trees are there with four vertices labeled with different integers from the set {1, 2, 3, 4}