Problem Statement

There are N giants, named 1 to N. When giant i stands on the ground, their shoulder height is A_i, and their head height is B_i.
You can choose $a permutation (P_1, P_2, \ldots, P_N)$ of $(1, 2, \ldots, N)$ and stack the N giants according to the following rules:

• First, place giant P_1 on the ground. The giant P_1's shoulder will be at a height of A_{P_1} from the ground, and their head will be at a height of B_{P_1} from the ground.

• For $i = 1, 2, \ldots, N - 1$ in order, place giant P_{i + 1} on the shoulders of giant P_i. If giant P_i's shoulders are at a height of t from the ground, then giant P_{i + 1}'s shoulders will be at a height of t + A_{P_{i + 1}} from the ground, and their head will be at a height of t + B_{P_{i + 1}} from the ground.

Find the maximum possible height of the head of the topmost giant P_N from the ground.

Input

The input is given from Standard Input in the following format:
N
A_1 B_1
A_2 B_2
$\vdots$
A_N B_N

Output

Print the answer.

Constraints

• $2 \leq N \leq 2 \times 10^5$
• $1 \leq A_i \leq B_i \leq 10^9$
• All input values are integers.

Sample Input 1

3
4 10
5 8
2 9

Sample Output 1

18

If (P_1, P_2, P_3) = (2, 1, 3), then measuring from the ground, giant 2 has a shoulder height of 5 and a head height of 8, giant 1 has a shoulder height of 9 and a head height of 15, and giant 3 has a shoulder height of 11 and a head height of 18.
The head height of the topmost giant from the ground cannot be greater than 18, so print 18.

Sample Input 2

5
1 1
1 1
1 1
1 1
1 1

Sample Output 2

5

Sample Input 3

10
690830957 868532399
741145463 930111470
612846445 948344128
540375785 925723427
723092548 925021315
928915367 973970164
563314352 832796216
562681294 868338948
923012648 954764623
691107436 891127278

Sample Output 3

7362669937

见题面 Input 部分

见题面 Output 部分