Problem statement

Real variables $ x_1, x_2, ..., x_N $ satisfy the following conditions.

1. $0 \ leq x_i \ leq 1$ ($1 \ leq i \ leq N$)
2. $w_1x_1 + w_2x_2 + ... + w_Nx_N \ leq W$

At this time, find the maximum value that $ v_1x_1 + v_2x_2 + ... + v_Nx_N $ can take. It is known that such a maximum actually exists.

Constraint

• $1 \ leq N \ leq 10 ^ 5$
• $1 \ leq W \ leq 10 ^ 5$
• $-10 ^ 4 \ leq w_i \ leq 10 ^ 4$
• $-10 ^ 4 \ leq v_i \ leq 10 ^ 4$

input

Input follows the following format. All given numbers are integers.

$ N $ $ W $
$ w_1 $ $ v_1 $
$ w_2 $ $ v_2 $
$ ... $
$ w_N $ $ v_N $

output

Output the maximum possible value of $ v_1x_1 + v_2x_2 + ... + v_Nx_N $ on one line. The output must not have an error greater than $ 10 ^ {-3} $.

Examples

Input

1 1
3 1

Output

0.333333

Input

2 3
3 3
1 2

Output

4.000000

Input

2 1
-1 -3
3 10

Output

3.666667

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