Classify the following sentence according to the type of noun it contains. Output 1 for proper noun, 2 for common noun and 3 for collective noun.
The herd of cows is running across the field.
3 for collective noun.
Complete the following task based on the instruction and optional input provided.### Instruction:
Classify the following sentence according to the type of noun it contains. Output 1 for proper noun, 2 for common noun and 3 for collective noun.

### Input:
The herd of cows is running across the field.

### Output:
3 for collective noun.