#include <iostream>
#include <algorithm>
using namespace std;
int main() {
long long n;
cin >> n;
long long a[n], b[n];
for (long long i =0; i < n;i++) {
cin>>a[i]>>b[i];
}
pair<long long, long long> art[n];
for (long long i = 0; i <n; i++) {
art[i] = {a[i], b[i]};
}
sort(art, art + n);
long long ans = art[n-1].second;
for (long long i = 0; i<n; i++) {
long long sum= 0;
long long mins= art[i].first;
long long maxs= art[i].first;
for (long long j = i; j< n; j++) {
sum += art[j].second;
mins = min(mins, art[j].first);
maxs = max(maxs, art[j].first);
long long cur = sum - (maxs - mins);
ans = max(ans, cur);
}
}
cout << ans << endl;
return 0;
}
