Suppose that p→,q→ and r→  are three non-coplanar vectors in ℝ3.  Let the components of a vector  along  p→,q→ and  r→ be 4, 3 and 5, respectively. If the components of this vector s→  along −p→+q→+r→,p→−q→+r,−p→−q→+r→  are x,y and  z respectively, then the value of 2x+y+z  is