N = int(input())
C, V = map(int, input().split())

inf = 10 ** 18
dp = [inf] * (2 * N + 1)
dp[1] = 0
for i in range(1, 2 * N + 1):
    for j in range(2 * i, 2 * N + 1, i):
        dp[j] = min(dp[j], dp[i] + C + V * (j//i - 1))
        
ans = inf
for i in range(N, 2 * N + 1):
    ans = min(ans, dp[i])
print(ans)