Begin   Step  1: Setting up the decision hierarchy by breaking down the decision problem into a       hierarchy of interrelated decision elements, as a tree containing the overall goal at       the top with many levels of criteria and subcriteria in between and the alternatives       at the bottom   Step  2: Collecting input data by pairwise comparisons of decision elements   Step  3: Using the eigenvalue method to estimate the relative weights of decision elements   Step  4: Aggregating the relative weights of decision elements to arrive at a set of ratings for       the decision alternatives. End.

Algorithm 1: The algorithm of analytic hierarchy process.