There's a bridge which is guarded by a devil who stays in the middle of the bridge.
It takes 6 minutes to cross the bridge in a constant speed(can only be crossed in a constant speed. don't ask why).
Devil sleeps for two minutes and stay awake for two minutes in a continuous loop.
And every time he wakes up he continuously checks both sides of the bridge and put any one that's on or passed his spot back on the shore he came from. He doesn't do anything to those who haven't reached his spot(middle).
How can you cross the bridge?