#include<bits/stdc++.h>
using namespace std;
#define ALL(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define INF 1000000000
#define mod 1000000007
using ll=long long;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

template<typename T>//コストの型(いじる必要なし)
struct Kruskal{
  
    struct edge{
        int from,to;
        T cost;
        int used;
        edge(int from,int to,T cost):
        from(from),to(to),cost(cost),used(0){}
        bool operator<(const edge& e) const{
            return cost<e.cost;
        }
    };
 
    int n;
    vector<int> siz,par;
    vector<edge> es;
    Kruskal(){}
    Kruskal(int n):n(n),siz(n,1),par(n){
        iota(par.begin(),par.end(),0);
    }
    
    //UF
    int root(int x){
        return (x==par[x]?x:(par[x]=root(par[x])));
    }
    bool sameParent(int x,int y){
        return (root(x)==root(y));
    }
    void unite(int x,int y){
        x=root(x);y=root(y);
        if(x==y) return;
        if(siz[x]<siz[y]) swap(x,y);
        siz[x]+=siz[y];par[y]=x;
    }
 
    void add_edge(int u,int v,T c){
        es.emplace_back(u,v,c);
    }
    T build(){
        sort(es.begin(),es.end());
        T res=0;
        for(auto &e:es){
            if(!sameParent(e.from,e.to)){
                //どんな最小全域木か知るならここをいじる
                //cout<<"--adding edge--"<<endl;
                //cout<<e.from<<" to "<<e.to<<" cost:"<<e.cost<<endl;
                res+=e.cost;
                unite(e.from,e.to);
                e.used=1;
            }
        }
        return res;
    }
};


signed main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int n;cin>>n;
    int s=n;
    ll c[n],d[n],sum=0;
    rep(i,n){
        cin>>c[i]>>d[i];
        sum+=c[i];
    }
    Kruskal<ll> g(n+1);
    rep(i,n) g.add_edge(s,i,c[i]);
    rep(i,n-1) g.add_edge(i,i+1,d[i+1]);
    cout<<g.build()+sum<<endl;
    return 0;
}