At ACKME Corporation, the annual company picnic has one very important rule: nobody should have to spend their day off with their boss. As the data science intern, your job is to help draw up the invitation list for the best possible company picnic. Luckily, ACKME has through careful evaluation assigned each employee a “fun rating”, and your task is simply to figure out the maximum total fun (summing over all invitees) for a company picnic.

The$n$ employees at ACKME are numbered$0, 1, \ldots , (n-1),$ and every employee except$\textrm{Employee}~ 0$ (the CEO) has exactly one boss. You can invite anyone, or their boss, to the picnic, but not both.

In the following diagrams, there is a visualization of the second and third sample inputs. The top number in each node is the employee number, and the bottom number is that employee’s fun rating. In each case, the rounded nodes denote the employees invited to the picnic. (These are possible optimal invitee lists; in general, there may be more than one optimal invitee list for any test case.)

Input

The first line of input contains a positive integer,$n \leq 200\, 000,$ specifying the number of employees. This is followed by$n$ lines, each of which gives the information for one of the employees, in order of increasing employee number (so the first of these$n$ lines is for$\textrm{Employee}~ 0).$ Each such line contains two space-separated numbers, the first of which is the employee’s fun rating, a non-negative integer no larger than$1\, 000\, 000,$ and the second of which is the employee number of the employee’s boss, an integer in the range$0 \ldots (n-1).$ Note that the “boss” listed for$\textrm{Employee}~ 0$ (who doesn’t actually have a boss) is$\textrm{always}~ 0,$ but this does not affect whether$\textrm{Employee}~ 0$ can be invited to the picnic.

It is guaranteed that the given employee-boss relationships yield a single hierarchy containing all$n$ employees, with$\textrm{Employee}~ 0$ at the top (ignoring the self-loop at$\textrm{Employee}~ 0).$

Output

Output a single non-negative integer, the maximum possible sum of invitee fun ratings.

816 0166 715 7359 277 7187 3211 783 0

829

101116 04848 7359 04118 9516 04298 12941 4996 0808 91120 2

13831

153815 01309 132778 06772 41469 13574 14899 04668 122585 617219 6761 41050 142391 1312889 034941 8

83602