from heapq import heappush, heappop

INF = 1 << 62
N = int(input())
C, V = map(int, input().split())

q = [(C, 1, 1)]
used = set()
while q:
    cost, n, cb = heappop(q)
    if n >= N:
        print(cost)
        break

    if (n, cb) in used: continue
    used.add((n, cb))

    heappush(q, (cost+V, n+cb, cb))
    if n > cb:
        heappush(q, (cost+C, n, n))