n = gets.to_i
c, v = gets.split.map(&:to_i)

ans = nil

n.times do |i|
  a, b, cost = 1, 0, 0
  (i + 1).times do # c+v
    a, b, cost = 2 * a, a, cost + c + v
    # p ['c+v =>', a, b, cost]
    break if a >= n
  end
  while a < n  # v
    a, b, cost = a + b, b, cost + v
    # p ['v =>', a, b, cost]
  end

  ans = ans == nil ? cost : [ans, cost].min
end

p ans