Construct a flow chart to explain the steps to become a doctor.
```
Start
|
v
Earn a bachelor's degree in a science-related field
(2.1) Complete pre-med requirements and take MCAT
|
v
Apply to medical school 
(3.1) Complete four years of medical school (MD or DO degree)
|
v
Complete a residency program in a chosen specialty (3-7 years, depending on specialty)
|
v
Obtain a license to practice medicine by passing required medical board exams
|
v
Apply for board certification (Optional)
|
V
End: Practice Medicine as a Doctor 
```
Complete the following task based on the instruction and optional input provided.### Instruction:
Construct a flow chart to explain the steps to become a doctor.

### Output:
```
Start
|
v
Earn a bachelor's degree in a science-related field
(2.1) Complete pre-med requirements and take MCAT
|
v
Apply to medical school 
(3.1) Complete four years of medical school (MD or DO degree)
|
v
Complete a residency program in a chosen specialty (3-7 years, depending on specialty)
|
v
Obtain a license to practice medicine by passing required medical board exams
|
v
Apply for board certification (Optional)
|
V
End: Practice Medicine as a Doctor 
```