Rewrite this sentence about a 50 mile marathon
The 50 mile marathon was a difficult race to complete.
Completing the marathon which spanned 50 miles proved to be a challenging task.
Complete the following task based on the instruction and optional input provided.### Instruction:
Rewrite this sentence about a 50 mile marathon

### Input:
The 50 mile marathon was a difficult race to complete.

### Output:
Completing the marathon which spanned 50 miles proved to be a challenging task.