Please help:

[10 pts] Let n > 3 be a natural number. Consider K, the complete graph on n vertices. (a) (5pts) Let k be the minimum number of edges that must be removed from K, such that the resulting graph is a tree. Determine the value of k as an expression in terms of n. Then indicate how to remove the minimum number of edges of K, such that the resulting graph is a tree with n vertices. (b) (5pts) Let / be the minimum number of nodes that must be removed (recall that removing a node removes also its incident edges) such that the resulting graph is a tree. Determine the value of & as an expression in terms of n. Then indicate how to remove the minimum number of nodes of K, such that the resulting graph is a tree