I am new to PyTorch.

When I was reading some examples, I have some questions.

Latest github example of mnist, in line 15 there is a number 320 in nn.Linear(), but I don’t know how to get that number.

```
class Net(nn.Module):
def __init__(self):
super(Net, self).__init__()
self.conv1 = nn.Conv2d(1, 10, kernel_size=5)
self.conv2 = nn.Conv2d(10, 20, kernel_size=5)
self.conv2_drop = nn.Dropout2d()
self.fc1 = nn.Linear(320, 50)
self.fc2 = nn.Linear(50, 10)
```

I only know that without conv2_drop, in fc1 it should be 20*5*5, but I don’t get how 320 come.

Thank you so much if you can help me.