To analyze the complexity of the following procedure P, we will use the following assumptions: Suppose P and B are both procedures. B takes $\theta(\sqrt{m})$ time to compute, where $m$ is the size of B's input; each statement line in and outside the loop counts 1 step.

Procedure P(array1[a1, a2, ..., an])
1. if n<9 exit.
2. call B(array1[a1, a2, ..., an])
   declare new empty array2, array3, array4;
3. for (i=1 to n)
4. { if ((i mod 9)=0)   insert ai into array2;
5.   if ((i mod 9)=3)   insert ai into array3;
6.   if ((i mod 9)=6)   insert ai into array4 }
8. call P( array2 );
9. call P( array3 );
10. call P (array4);