A statistician working for the Department of the Interior is constructing a systematic random sample of trees in a forest preserve. All trees have been identified and numbered with a non-invasive number attached to the bark. The statistician wishes to estimate the mean height of the trees in the forest preserve, and has calculated an appropriate sample size of n=43 trees. The 587th of the 731 trees in the preserve was selected as the first observation in the sample. What is the tree number of the second observation in the sample?