#include <iostream>
#include <vector>
#include <algorithm>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/hash_policy.hpp>
#define int long long
#define $AzH_TxdmN$ ios_base::sync_with_stdio(0);cin.tie(nullptr);cout.tie(nullptr);
#pragma GCC target("sse,sse2,sse3,ssse3,popcnt,abm,mmx,tune=native")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("fast-math")
#define pb push_back
#define ep emplace_back
#define all(v) v.begin(),v.end()
#define pii pair<int,int>
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> __indexed_set;
typedef tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update> __indexed_multiset;
const int sz = 5e5+9;
const int MOD = 1e9+7;
const int INF = 1e18;
pii a[sz];
int n,k;
void solve()
{
cin>>n;
for (int i = 1; i <= n; ++i)
{
cin>>a[i].first>>a[i].second;
}
sort(a+1,a+1+n);
int res = 0,curr = 0,currmn = INF,currmx = -INF,nwmn,nwmx;
for (int i = 1; i <= n; ++i)
{
nwmn = min(currmn,a[i].first);
nwmx = max(currmx,a[i].first);
if (curr+a[i].second-(nwmx-nwmn) < a[i].second)
{
curr = a[i].second;
currmn = a[i].first;
currmx = a[i].first;
}
else
{
currmn = nwmn;
currmx = nwmx;
curr += a[i].second;
}
res = max(res,curr - (currmx-currmn));
}
cout<<res<<'\n';
}
signed main()
{
$AzH_TxdmN$
int t = 1;
//cin>>t;
while (t--)
{
solve();
}
}
