Consider a computing system with 6 frames of physical memory, in which it starts to a process is running. The process references data on the following pages virtual memory: 4, 7, 2, 3, 7, 1, 6, 5, 3, 6, 4, 2, 7, 8, 9, 6, 8, 1, 5, 2, 9, 7 Assuming that initially all frames are empty, how many page faults will occur if is the First-In-First-Out (FIFO) page replacement algorithm used?