/*  -*- coding: utf-8 -*-
 *
 * f.cc: F: 
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>

using namespace std;

/* constant */

const int MAX_N = 200000;

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);

  ll ssum = 0, minb = 0, maxsum = 0;
  for (int i = 0; i < n; i++) {
    ll xi;
    int si;
    scanf("%lld%d", &xi, &si);

    ll b = ssum - xi;
    ssum += si;
    ll a = ssum - xi;
    if (minb > b) minb = b;
    ll sum = a - minb;
    if (maxsum < sum) maxsum = sum;
  }

  printf("%lld\n", maxsum);
  return 0;
}

### Prompt

Develop a solution in Cpp to the problem described below:

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.

Examples

Input

5
10 20
40 50
60 30
70 40
90 10


Output

90


Input

5
10 2
40 5
60 3
70 4
90 1


Output

5


Input

4
1 100
3 200
999999999999999 150
1000000000000000 150


Output

299

### Response

```cpp
/*  -*- coding: utf-8 -*-
 *
 * f.cc: F: 
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>

using namespace std;

/* constant */

const int MAX_N = 200000;

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);

  ll ssum = 0, minb = 0, maxsum = 0;
  for (int i = 0; i < n; i++) {
    ll xi;
    int si;
    scanf("%lld%d", &xi, &si);

    ll b = ssum - xi;
    ssum += si;
    ll a = ssum - xi;
    if (minb > b) minb = b;
    ll sum = a - minb;
    if (maxsum < sum) maxsum = sum;
  }

  printf("%lld\n", maxsum);
  return 0;
}

```