local n, a, b = io.read("*n", "*n", "*n")
if n % 2 == 1 then
  --[[
  -a(n-1)-b <= a(n-1)-bn
  b(n-1)<=2a(n-1)
  b<=2a
  ]]
  local c1 = a * (n - 1) - b * n
  local c2 = -a * (n - 1) - b
  print(math.min(c1, c2))
else
  local c1 = a * (n - 1) - b * n
  local c2 = -a * (n - 1)
  local hn = mfl(n / 2)
  --[[
  (1, -1,)*k + (1, 1, )*(hn-k)
  => -2a * k + ((hn - k) * 2 - 1) * a - 2b * (hn - k)
  = k(-2a-2a+2b)+...
  ]]
  print(math.min(c1, c2))
end