n = int(input())
c, v = map(int, input().split())
dp = [1 << 30] * (n + 1)
dp[1] = 0
for i in range(1, n + 1):
    cost = c + dp[i]
    for j in range(2 * i, n + 1, i):
        cost += v
        dp[j] = min(dp[j], cost)
    dp[-1] = min(dp[-1], cost + v)
print(dp[-1])