def g;gets.split.map(&:to_f)end
X,Y=g
n,=g
L=(1..n).map{g}+[[X,Y,0]]
Memo=L.map{{}}
def dfs(a,left)
  x,y,=L[a]
  Memo[a][left]||=left[0]?(left.map{|i|
    t,u,=L[i]
    dfs(i,left-[i])+((x-t).abs+(y-u).abs)*(left.inject(0){|s,r|s+L[r][2]}+100.0)/120
  }.min):((X-x).abs+(Y-y).abs)*(100.0)/120
end
p dfs(n,[*0...n])+L.inject(0){|s,r|s+r[2]}