B. Friends and Presents
time limit per test 1 second
memory limit per test 256 megabytes
input standard input
output standard output

You have two friends. You want to present each of them several positive integers. You want to presentcnt1numbers to the first friend andcnt2numbers to the second friend. Moreover, you want all presented numbers to be distinct, that also means that no number should be presented to both friends.

In addition, the first friend does not like the numbers that are divisible without remainder by prime numberx. The second one does not like the numbers that are divisible without remainder by prime numbery. Of course, you're not going to present your friends numbers they don't like.

Your task is to find such minimum numberv, that you can form presents using numbers from a set1, 2, ..., v. Of course you may choose not to present some numbers at all.

A positive integer number greater than 1 is calledprimeif it has no positive divisors other than 1 and itself.

Input

The only line contains four positive integerscnt1,cnt2,x,y(1 ≤ cnt1, cnt2 < 109;cnt1 + cnt2 ≤ 109;2 ≤ x < y ≤ 3·104)— the numbers that are described in the statement. It is guaranteed that numbersx,yare prime.

Output

Print a single integer — the answer to the problem.

Sample test(s)
input
3 1 2 3
output
5
input
1 3 2 3
output
4
Note

In the first sample you give the set of numbers{1, 3, 5}to the first friend and the set of numbers{2}to the second friend. Note that if you give set{1, 3, 5}to the first friend, then we cannot give any of the numbers1,3,5to the second friend.

In the second sample you give the set of numbers{3}to the first friend, and the set of numbers{1, 2, 4}to the second friend. Thus, the answer to the problem is4.

#include <stdio.h>
int main() {
	int cnt1, cnt2, x, y;
	scanf("%d %d %d %d", &cnt1, &cnt2, &x, &y);
	int l=1, r=0x7FFFFFFF, m;
	while(l<r) {
		m=l+(r-l)/2;
		if(cnt1 <= m-(m/x) && cnt2 <= m-(m/y) && cnt1+cnt2 <= m-(m/(x*y)))
			r=m;
		else
			l=m+1;
	}
	printf("%d", r);
	return 0;
}

  

优质内容筛选与推荐>>
1、C#获取程序启动目录
2、MFC通过button控制编辑框是否显示系统时间
3、AssionShop开源B2C电子商务系统-(二)定单流程活动图状态图(转载)
4、centos7安装elasticsearch
5、模拟发送POST或Get请求


长按二维码向我转账

受苹果公司新规定影响,微信 iOS 版的赞赏功能被关闭,可通过二维码转账支持公众号。

    阅读
    好看
    已推荐到看一看
    你的朋友可以在“发现”-“看一看”看到你认为好看的文章。
    已取消,“好看”想法已同步删除
    已推荐到看一看 和朋友分享想法
    最多200字,当前共 发送

    已发送

    朋友将在看一看看到

    确定
    分享你的想法...
    取消

    分享想法到看一看

    确定
    最多200字,当前共

    发送中

    网络异常,请稍后重试

    微信扫一扫
    关注该公众号





    联系我们

    欢迎来到TinyMind。

    关于TinyMind的内容或商务合作、网站建议,举报不良信息等均可联系我们。

    TinyMind客服邮箱:support@tinymind.net.cn