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#8331
Subtask

Bitaro the Brave 2 1s 1024MB

Problems

Bitaro, the brave hero, has set out on an adventure to defeat monsters.

There are N monsters labeled from 1 to N. To defeat the i-th monster, Bitaro must have a strength of at least Aᵢ. Upon defeating the i-th monster, his strength increases by Bᵢ.

Bitaro follows the strategy below to defeat all the monsters:

Start with a specific monster j (1 ≤ j ≤ N) and defeat the monsters in order: j, j+1, …, N.

If j ≥ 2, then proceed to defeat the monsters 1, 2, …, j−1 in sequence.

Given the information about the monsters (arrays A and B), determine the minimum initial strength x that Bitaro needs to defeat all the monsters.


Input

The first line contains an integer N.

The second line contains N space-separated integers A₁, A₂, …, A_N.

The third line contains N space-separated integers B₁, B₂, …, B_N.

[Constrains]

  • 2 ≤ N ≤ 500\ 000

  • 0 ≤ A_i ≤ 10^9 (1 ≤ i ≤ N)

  • 0 ≤ B_j ≤ 10^9 (1 ≤ j ≤ N)

  • Given values are all integers.


Output

Print a single integer x, the minimum initial strength required for Bitaro to defeat all the monsters.


Subtask

# Score Condition
#110

N ≤ 2,000 and the minimum initial strength x is at most 10

#221

N ≤ 2,000

#319

The minimum initial strength x is at most 10

#422

Bᵢ = 1 for all i (1 ≤ i ≤ N)

#528

No additional constraints


Example #1

5
1 3 2 8 6
4 3 1 1 2
1

Starting with x = 1 and processing monsters 1 through 5 in order:

Monster 1: 1 ≥ 1, new strength = 1+4 = 5

Monster 2: 5 ≥ 3, new strength = 5+3 = 8

Monster 3: 8 ≥ 2, new strength = 8+1 = 9

Monster 4: 9 ≥ 8, new strength = 9+1 = 10

Monster 5: 10 ≥ 6, new strength = 10+2 = 12

Thus, x = 1 is sufficient.


Example #2

5
1 6 3 3 2
1 2 1 0 1
3

Starting with x = 3 and beginning from monster 3, the sequence of battles ensures that each monster’s requirement is met. Hence, the answer is 3.


Example #3

10
11 9 8 12 7 7 8 12 9 10
1 1 1 1 1 1 1 1 1 1
9

By choosing an appropriate starting monster (e.g., monster 5), x = 9 is sufficient for Bitaro to defeat all monsters.


Example #4

7
1125 638 0 37 737 820 1202
23 984 558 350 52 345 580
0

Starting with x = 0 from monster 3 works since the 3rd monster requires 0 strength. Then, subsequent strength increases allow Bitaro to defeat the remaining monsters.


Source

JOI 2025

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