def In() -> int:
    return int(input())


def SplitIn() -> list[int]:
    return list(map(int, input().split()))


def main():
    d = In()
    a, b = SplitIn()

    maxv = 10000000
    for p in range(d + 1):
        maxv = min(maxv, p * a + (d - p) * b)

    print(maxv)


if __name__ == "__main__":
    main()