##质能方程
$E=mc^2$
```flow
st=>start: Start
e=>end
op=>operation: My Operation
cond=>condition: Yes or No?
st->op->cond
cond(yes)->e
cond(no)->op
```
##质能方程
$E=mc^2$
```flow
st=>start: Start
e=>end
op=>operation: My Operation
cond=>condition: Yes or No?
st->op->cond
cond(yes)->e
cond(no)->op
```