Find out the second most common letter in the given sentence. Output the letter directly.
Efficient algorithms are necessary for data processing.
The second most common letter in the given sentence "Efficient algorithms are necessary for data processing." is "e"
Complete the following task based on the instruction and optional input provided.### Instruction:
Find out the second most common letter in the given sentence. Output the letter directly.

### Input:
Efficient algorithms are necessary for data processing.

### Output:
The second most common letter in the given sentence "Efficient algorithms are necessary for data processing." is "e"