In the sentence, "Jack received a birthday present from his aunt Mary," identify the subject.
The subject in the sentence "Jack received a birthday present from his aunt Mary" is "Jack".
Complete the following task based on the instruction and optional input provided.### Instruction:
In the sentence, "Jack received a birthday present from his aunt Mary," identify the subject.

### Output:
The subject in the sentence "Jack received a birthday present from his aunt Mary" is "Jack".