Maybe billions! Imagine billions of brown people coming for our land and our women. 

That's why we need a wall. A 'uge wall. AND a moat with sharks with laser beams on their heads. The brown hoards are coming.

There is about 9 million miles of border, so if we draft every adult Canadian into the Armed Forces, and arm them with an assault rifle and a shark (BTW, we better start a breeding program ASAP), we could have the border fully defended from brown skinned 5 year olds with 1 sentry per mile.

Of course, the economy would collapse, but at least we'd be safe from the hoards of brown skinned kids crossing he border.