#include using namespace std; static const long long INF = 1e18; int main() { size_t N; cin >> N; vector C(N), D(N); for (int i = 0; i < N; i++) cin >> C[i] >> D[i]; auto get_min = [&](int l, int r) { return *min_element(C.begin() + l, C.begin() + r); }; deque > Q; multiset X; auto add_back = [&](long long a, long long b) { long long v = a; while (Q.size() && Q.back().second <= b) { v = max(Q.back().first, v); X.erase(X.find(Q.back().first + Q.back().second)); Q.pop_back(); } if(Q.empty() || Q.back().first <= v ) { Q.emplace_back(v, b); X.insert(b + v); } }; add_back(D[0], -C[0]); for (int i = 1; i < N; i++) { add_back(*X.rbegin() + D[i], -C[i]); } cout << accumulate(C.begin(), C.end(), 0ll) + accumulate(D.begin(), D.end(), 0ll) - *X.rbegin() << endl; }