Given the input, find the length of the longest word in the sentence.
The picture hanging on the wall has a beautiful blue sky and the river in the background.
The length of the longest word in the given sentence is 11.
Complete the following task based on the instruction and optional input provided.### Instruction:
Given the input, find the length of the longest word in the sentence.

### Input:
The picture hanging on the wall has a beautiful blue sky and the river in the background.

### Output:
The length of the longest word in the given sentence is 11.