Since such a tree does not exist for all strings, formula_1 is padded with a terminal symbol not seen in the string (usually denoted codice_1). This ensures that no suffix is a prefix of another, and that there will be formula_5 leaf nodes, one for each of the formula_5 suffixes of formula_1. Since all internal non-root nodes are branching, there can be at most "n" −  1 such nodes, and "n" + ("n" − 1) + 1 = 2"n" nodes in total ("n" leaves, "n" − 1 internal non-root nodes, 1 root).