#arc149b. [arc149_b]Two LIS Sum

[arc149_b]Two LIS Sum

Problem Statement

For a sequence P=(P1,ldots,PN)P = (P_1, \\ldots, P_N), let mathrmLIS(P)\\mathrm{LIS}(P) denote the length of a longest increasing subsequence.

You are given permutations A=(A1,ldots,AN)A = (A_1, \\ldots, A_N) and B=(B1,ldots,BN)B = (B_1, \\ldots, B_N) of integers from 11 through NN. You may perform the following operation on these sequences any number of times (possibly zero).

  • Choose an integer ii such that 1leqileqN11\\leq i\\leq N-1. Swap AiA_i and Ai+1A_{i+1}, and swap BiB_i and Bi+1B_{i+1}.

Find the maximum possible final value of mathrmLIS(A)+mathrmLIS(B)\\mathrm{LIS}(A) + \\mathrm{LIS}(B).

What is a longest increasing subsequence?

A subsequence of a sequence is a sequence obtained by removing zero or more elements from the original sequence and then concatenating the remaining elements without changing the order. For instance, (10,30)(10,30) is a subsequence of (10,20,30)(10,20,30), but (20,10)(20,10) is not a subsequence of (10,20,30)(10,20,30).

A longest increasing subsequence of a sequence is a subsequence of that sequence with the greatest length among its subsequences that are strictly increasing.

Constraints

  • 2leqNleq3times1052\\leq N\\leq 3\\times 10^5
  • 1leqAileqN1\\leq A_i\\leq N
  • 1leqBileqN1\\leq B_i\\leq N
  • AineqAjA_i\\neq A_j and BineqBjB_i\\neq B_j, if ineqji\\neq j.

Input

The input is given from Standard Input in the following format:

NN A1A_1 ldots\\ldots ANA_N B1B_1 ldots\\ldots BNB_N

Output

Print the maximum possible final value of mathrmLIS(A)+mathrmLIS(B)\\mathrm{LIS}(A) + \\mathrm{LIS}(B).


Sample Input 1

5
5 2 1 4 3
3 1 2 5 4

Sample Output 1

8

Here is one way to achieve mathrmLIS(A)+mathrmLIS(B)=8\\mathrm{LIS}(A) + \\mathrm{LIS}(B) = 8.

  • Do the operation with i=2i = 2. Now, A=(5,1,2,4,3)A = (5,1,2,4,3), B=(3,2,1,5,4)B = (3,2,1,5,4).
  • Do the operation with i=1i = 1. Now, A=(1,5,2,4,3)A = (1,5,2,4,3), B=(2,3,1,5,4)B = (2,3,1,5,4).
  • Do the operation with i=4i = 4. Now, A=(1,5,2,3,4)A = (1,5,2,3,4), B=(2,3,1,4,5)B = (2,3,1,4,5).

Here, AA has a longest increasing subsequence (1,2,3,4)(1,2,3,4), so mathrmLIS(A)=4\\mathrm{LIS}(A)=4, and BB has a longest increasing subsequence (2,3,4,5)(2,3,4,5), so mathrmLIS(B)=4\\mathrm{LIS}(B)=4.


Sample Input 2

5
1 2 3 4 5
1 2 3 4 5

Sample Output 2

10

You can decide not to perform the operation at all to achieve mathrmLIS(A)+mathrmLIS(B)=10\\mathrm{LIS}(A) + \\mathrm{LIS}(B) = 10.