Suppose you have a simple hashing system for storing integers that just uses a compression function to determine the array slot to use and uses linear probing for collision resolution. _____________ collision(s) occur if the size of the array is 20 and the following sequence of integers is added:

5 10 15 20 25

Each time the chosen array slot is already occupied should be counted as a collision; in other words, multiple collisions can occur when adding a single element due to collisions happening while linear probing. Your answer should be a number.