 Combining this with the inequality relating amortized time and actual time over sequences of operations, this shows that any sequence of "n" dynamic array operations takes O("n") actual time in the worst case, despite the fact that some of the individual operations may themselves take a linear amount of time.When the dynamic array includes operations that decrease the array size as well as increasing it, the potential function must be modified to prevent it from becoming negative.One way to do this is to replace the formula above for Φ by its absolute value.