Rewrite this text in third person perspective.
I can't believe how much I have accomplished in such a short amount of time.
They couldn't believe how much they had accomplished in such a short amount of time.
Complete the following task based on the instruction and optional input provided.### Instruction:
Rewrite this text in third person perspective.

### Input:
I can't believe how much I have accomplished in such a short amount of time.

### Output:
They couldn't believe how much they had accomplished in such a short amount of time.