What to do with Overflow in VBA?

Question

Visual Basic

There is this code:

Private Sub CommandButton2_Click()
Dim speed As Long, minute As Long, hour As Long, day As Long

speed = 299792
minute = 60 * speed
hour = (60 * 60) * speed
day = 60 * 60 * CLng(24)
day = CLng(day) * CLng(speed)

TextBox1.Text = minute
TextBox2.Text = hour
TextBox3.Text = day
End Sub

On line 8, an error pops up:

Run-time error '6':
Overflow

What to do?
(Line 8 is day = CLng(day) * CLng(speed))