#include<bits/stdc++.h>
using namespace std;
using i64 = int64_t;
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
i64 N;
cin >> N;
i64 mi = INT64_MAX, ma = 0, suma = 0;;
vector<pair<i64, i64>> table(N);
for (i64 i = 0; i < N; i++)
{
cin >> table[i].first >> table[i].second;
suma += table[i].second;
mi = min(mi, table[i].first);
ma = max(ma, table[i].first);
}
sort(table.begin(), table.end());
vector<pair<i64, i64>> pra(N);
vector<pair<i64, i64>> lew(N);
for (i64 i = 1; i < N; i++)
{
pra[i].first = pra[i - 1].first + (table[i].first - table[i - 1].first) - table[i - 1].second;
pra[i].second = max(pra[i - 1].second, pra[i].first);
//cout << pra[i].first << " : " << pra[i].second << "\n";
}
//cout << "\n";
for (i64 i = N - 2; i >= 0; i--)
{
lew[i].first = lew[i + 1].first + (table[i + 1].first - table[i].first) - table[i + 1].second;
lew[i].second = max(lew[i + 1].second, lew[i].first);
//cout << lew[i].first << " : " << lew[i].second << "\n";
}
i64 maxx = 0;
for (i64 i = 0; i < N; i++)
{
maxx = max(maxx, pra[i].second + lew[i].second);
}
cout << suma + mi + maxx - ma << "\n";
return 0;
}
