#include <bits/stdc++.h>

using namespace std;
static const long long INF = 1e18;

int main() {
    size_t N;
    cin >> N;
    vector<long long> 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<pair<long long, long long> > Q;
    multiset<long long> X;
    auto add_back = [&](long long a, long long b) {
        Q.emplace_back(a, b);
        X.insert(a + b);
    };
    auto add_front = [&](long long a, long long b) {
        Q.emplace_front(a, b);
        X.insert(a + b);
    };
    auto upd = [&](long long c) {
        long long v = -INF;
        while (!Q.empty() && Q.front().second <= c) {
            v = max(Q.front().first, v);
            X.erase(X.find(Q.front().first + Q.front().second));
            Q.pop_front();
        }
        if (v != -INF) {
            add_front(v, c);
        }
    };
    add_back(D[0], -C[0]);
    for (int i = 1; i < N; i++) {
        add_back(*X.rbegin() + D[i], -C[i]);
        upd(-C[i]);
    }
    cout << accumulate(C.begin(), C.end(), 0ll) + accumulate(D.begin(), D.end(), 0ll) - *X.rbegin() << endl;


}