Combine the given two facts to write a concluding fact. Note that there should be some parts of the first and second facts that are not mentioned in this conclusion fact. Your combined fact should be the result of a chain between the two facts. Chains form when two facts connect together to produce a concluding fact. An example of a chain is: "pesticides cause pollution" (fact1) + "pollution can harm animals" (fact2) → "pesticides can harm animals" (conclusion fact). Parts of the concluding fact overlap with the first and the second fact. To construct such a  concluding fact, a useful way is to borrow the subject from one fact and the ending conclusions from another fact.

Input: Consider Input: Fact 1: the number of rings in a tree trunk can be used to estimate the age of the tree. 
Fact 2: If you want to find the age of a forest, you find the tree with the highest number of tree rings.

Output: to estimate the age of a forest, find the tree with the highest number of rings.


Input: Consider Input: Fact 1: Mating is generally preceded by courtship. 
Fact 2: Courtship patterns vary with species.

Output: mating patterns vary with species.


Input: Consider Input: Fact 1: sugar causes food to taste sweet. 
Fact 2: Saccharides consisting of one simple sugar unit are called monosaccharides .


Output: monosaccharides cause food to taste sweet.