Consider an analytical algorithm $A$ to take $n$ items as input set. When input size $n \le 4$, the process will terminate and return results, otherwise it will divide the input set into 4 roughly equal-size subsets; 2 of 4 subsets serve as samples and act as inputs to recursively apply $A$ twice; the results of the previous 2 outcomes (from the 2 recursive $A$ executions) each has $n/4$ items; then we will use a procedure $I$ to integrate the 2 outcomes, where $I$ takes $\theta(\sqrt{m/4})$ when inputs are 2 sets of size $m$ subsets. What about this algorithm are true?