CF605C.Freelancer's Dreams

普及/提高-

通过率:0%

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题目描述

Mikhail the Freelancer dreams of two things: to become a cool programmer and to buy a flat in Moscow. To become a cool programmer, he needs at least pp experience points, and a desired flat in Moscow costs qq dollars. Mikhail is determined to follow his dreams and registered at a freelance site.

He has suggestions to work on nn distinct projects. Mikhail has already evaluated that the participation in the ii -th project will increase his experience by aia_{i} per day and bring bib_{i} dollars per day. As freelance work implies flexible working hours, Mikhail is free to stop working on one project at any time and start working on another project. Doing so, he receives the respective share of experience and money. Mikhail is only trying to become a cool programmer, so he is able to work only on one project at any moment of time.

Find the real value, equal to the minimum number of days Mikhail needs to make his dream come true.

For example, suppose Mikhail is suggested to work on three projects and a1=6a_{1}=6 , b1=2b_{1}=2 , a2=1a_{2}=1 , b2=3b_{2}=3 , a3=2a_{3}=2 , b3=6b_{3}=6 . Also, p=20p=20 and q=20q=20 . In order to achieve his aims Mikhail has to work for 2.52.5 days on both first and third projects. Indeed, a12.5+a20+a32.5=62.5+10+22.5=20a_{1}·2.5+a_{2}·0+a_{3}·2.5=6·2.5+1·0+2·2.5=20 and b12.5+b20+b32.5=22.5+30+62.5=20b_{1}·2.5+b_{2}·0+b_{3}·2.5=2·2.5+3·0+6·2.5=20 .

输入格式

The first line of the input contains three integers nn , pp and qq ( 1<=n<=100000,1<=p,q<=10000001<=n<=100000,1<=p,q<=1000000 ) — the number of projects and the required number of experience and money.

Each of the next nn lines contains two integers aia_{i} and bib_{i} ( 1<=ai,bi<=10000001<=a_{i},b_{i}<=1000000 ) — the daily increase in experience and daily income for working on the ii -th project.

输出格式

Print a real value — the minimum number of days Mikhail needs to get the required amount of experience and money. Your answer will be considered correct if its absolute or relative error does not exceed 10610^{-6} .

Namely: let's assume that your answer is aa , and the answer of the jury is bb . The checker program will consider your answer correct, if .

输入输出样例

  • 输入#1

    3 20 20
    6 2
    1 3
    2 6
    

    输出#1

    5.000000000000000
    
  • 输入#2

    4 1 1
    2 3
    3 2
    2 3
    3 2
    

    输出#2

    0.400000000000000
    

说明/提示

First sample corresponds to the example in the problem statement.

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