#include <bits/stdc++.h>
#include <unistd.h>

using namespace std;

#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}


typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const ll MOD = 1000000007;
//const ll MOD = 998244353;
const double pi = 3.14159265358979323846;
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { -1,0, 1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
// #define mp make_pair
//#define endl '\n'

int main() {
  int n;
  cin >> n;
  vl c(n), d(n);

  ll ans = 0;
  rep (i, n) {
    cin >> c[i] >> d[i];
    ans += c[i];
    ans += d[i];
  }

  vl dp(n + 1, INF);
  vl dp2(n + 1, INF);
  dp[0] = 0;
  dp2[0] = -d[0];

  deque<pll> cost_dp2;
  ll mi = INF;
  rep (i, n) {
    pll add(c[i], dp2[i]);
    ll temp = INF;
    while (cost_dp2.size() > 0) {
      if (cost_dp2.back().first >= c[i]) {
        temp = min(temp, cost_dp2.back().second);
        cost_dp2.pop_back();
      }
      else {
        break;
      }
    }
    
    if (temp < dp2[i]) {
      if (cost_dp2.size() == 0 or cost_dp2.back().second > temp) {
        cost_dp2.push_back(pll(c[i], temp));
        chmin(mi, c[i] + temp);
      }
    }
    else {
      if (cost_dp2.size() == 0 or cost_dp2.back().second > dp2[i]) {
        cost_dp2.push_back(pll(c[i], dp2[i]));
        chmin(mi, c[i] + dp2[i]);
      }
    }
    
    dp[i + 1] = mi;
    if (i + 1 != n) {
      dp2[i + 1] = dp[i + 1] - d[i + 1];
    }
    //DEBUG_VEC(cost_dp2);
    /*
    rep (i, cost_dp2.size() - 1) {
      assert(cost_dp2[i + 1].first > cost_dp2[i].first and cost_dp2[i + 1].second < cost_dp2[i].second);
    }
    //*/
    //DEBUG_VEC(dp);
    //DEBUG_VEC(dp2);
    //DEBUG(mi);
  }
  cout << dp[n] + ans << endl;
}