Consider the classic farmer, fox, goose, and grain problem. The farmer wants to move himself, the fox, the goose, and the edible grain from the west side to the east side of the river. Only he can row his small boat across the river, and he can only take one of his items with him at a time. If the fox is left with the goose, the goose will be eaten. If the goose is left with the grain, the grain will be eaten. It turns out that you can pose this as a graph search problem. Suppose we want to use A$*$ here. Describe a non$-$trivial admissible heuristic $($heuristic looks at the states and compute the cost for each state$)$ that we could use. Why admissible?