Contest Duration: - (local time) (90 minutes)
F - Capture /

Time Limit: 2 sec / Memory Limit: 256 MB

### 問題文

あなたは整数 L, R (L ≤ R) を選び、地点 L から地点 R までの両端を含む範囲、[L, R] に網を放ちます。すると、その範囲内のけものがすべて捕獲されます。ただし、網に R - L 円のコストがかかり、あなたの利益は (捕獲されたすべてのけもの i に対する s_i の合計) - (R - L) 円となります。

### 制約

• 1 ≤ N ≤ 2 × 10^5
• 1 ≤ x_1 < x_2 < ... < x_N ≤ 10^{15}
• 1 ≤ s_i ≤ 10^9
• 入力値はすべて整数である。

### 入力

N
x_1 s_1
x_2 s_2
:
x_N s_N


### 入力例 1

5
10 20
40 50
60 30
70 40
90 10


### 出力例 1

90


### 入力例 2

5
10 2
40 5
60 3
70 4
90 1


### 出力例 2

5


けものたちは入力例 1 と同じ位置にいますが、彼らの売値が大幅に下がっているため、二匹以上を狙うべきではありません。範囲 [L = 40, R = 40] に網を放つことで s_2 - (R - L) = 5 円の利益が得られ、これが最大です。

### 入力例 3

4
1 100
3 200
999999999999999 150
1000000000000000 150


### 出力例 3

299


Score : 100 points

### Problem Statement

In a long narrow forest stretching east-west, there are N beasts. Below, we will call the point that is p meters from the west end Point p. The i-th beast from the west (1 ≤ i ≤ N) is at Point x_i, and can be sold for s_i yen (the currency of Japan) if captured.

You will choose two integers L and R (L ≤ R), and throw a net to cover the range from Point L to Point R including both ends, [L, R]. Then, all the beasts in the range will be captured. However, the net costs R - L yen and your profit will be (the sum of s_i over all captured beasts i) - (R - L) yen.

What is the maximum profit that can be earned by throwing a net only once?

### Constraints

• 1 ≤ N ≤ 2 × 10^5
• 1 ≤ x_1 < x_2 < ... < x_N ≤ 10^{15}
• 1 ≤ s_i ≤ 10^9
• All input values are integers.

### Input

Input is given from Standard Input in the following format:

N
x_1 s_1
x_2 s_2
:
x_N s_N


### Output

When the maximum profit is X yen, print the value of X.

### Sample Input 1

5
10 20
40 50
60 30
70 40
90 10


### Sample Output 1

90


If you throw a net covering the range [L = 40, R = 70], the second, third and fourth beasts from the west will be captured, generating the profit of s_2 + s_3 + s_4 - (R - L) = 90 yen. It is not possible to earn 91 yen or more.

### Sample Input 2

5
10 2
40 5
60 3
70 4
90 1


### Sample Output 2

5


The positions of the beasts are the same as Sample 1, but the selling prices dropped significantly, so you should not aim for two or more beasts. By throwing a net covering the range [L = 40, R = 40], you can earn s_2 - (R - L) = 5 yen, and this is the maximum possible profit.

### Sample Input 3

4
1 100
3 200
999999999999999 150
1000000000000000 150


### Sample Output 3

299