n = int(input())
c, v = map(int, input().split())
ret = [c + v * (i - 1) for i in range(n + 1)]
ret[0] = ret[1] = 0
for i in range(2, n + 1):
    j = 2
    while i * j < n:
        ret[j * i] = min(ret[j * i], ret[i] + c + v * (j - 1))
        j += 1
    ret[n] = min(ret[n], ret[i] + c + v * (j - 1))
print(ret[n])