#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define s second
#define f first
#define pll pair <ll,ll>
#define pii pair <int,int>
#define left h*2,l,(l + r)/2
#define right h*2+1,(l + r)/2 + 1,r
using namespace std;
const int N = 5e5 + 5;
ll t[4*N],lz[4*N],p[N];
pll d[N];
void push(int h){
if (lz[h] == 0) return;
lz[h*2] += lz[h];
lz[h*2 + 1] += lz[h];
t[h*2] += lz[h];
t[h*2 + 1] += lz[h];
lz[h] = 0;
}
void upd(int h,int l,int r,int L,int R,ll val){
if (r < L || R < l) return ;
if (L <= l && r <= R){
t[h] += val;
lz[h] += val;
return;
}
push(h);
upd(left,L,R,val);
upd(right,L,R,val);
t[h] = max(t[h*2],t[h*2+1]);
}
ll get(int h,int l,int r,int L,int R){
if (r < L || R < l) return 0;
if (L <= l && r <= R) return t[h];
push(h);
return max(get(left,L,R),get(right,L,R));
}
signed main() {
ios_base::sync_with_stdio(0),cin.tie(NULL),cout.tie(NULL);
int n;
cin>>n;
for (int i = 1; i <= n; i++){
cin>>d[i].f>>d[i].s;
}
sort(d + 1,d + n + 1);
d[0].f = d[1].f;
for (int i = 1; i <= n; i++){
p[i] = p[i - 1] + d[i].s - (d[i].f - d[i - 1].f);
upd(1,1,n,i,i,p[i]);
}
ll ans = 0;
for (int i = 1; i <= n; i++){
ans = max(ans, get(1,1,n,i,n));
ll val = get(1,1,n,i,i);
upd(1,1,n,i + 1,n,-val + (d[i + 1].f - d[i].f));
}
cout<<ans;
}
