from heapq import heapify, heappop, heappush

n = int(input())
c, v = map(int, input().split())

H = [(c, 1, 1)]
heapify(H)
while H:
    cost, num, c_num = heappop(H)
    if num >= n:
        print(cost)
        break
    if c_num != num:
        heappush(H, (cost + c, num, num))
    heappush(H, (cost + v, num + c_num, c_num))