Name four consecutive US presidents.
George H. W. Bush (1989-1993), Bill Clinton (1993-2001), George W. Bush (2001-2009), and Barack Obama (2009-2017) are four consecutive US presidents.
Complete the following task based on the instruction and optional input provided.### Instruction:
Name four consecutive US presidents.

### Output:
George H. W. Bush (1989-1993), Bill Clinton (1993-2001), George W. Bush (2001-2009), and Barack Obama (2009-2017) are four consecutive US presidents.