#include<iostream>
#include<fstream>
#include<stdio.h>
#include<cstdio>
#include<stdlib.h>
#include<string>
#include<string.h>
#include<ctype.h>
#include<algorithm>
#include<cmath>
#include<set>
#include<queue>
#include<assert.h>
#include<stack>
#include<iomanip>
#include<vector>
#include<map>
#define PB(x) push_back(x)
#define MP(x, y) make_pair(x, y)
#define fi first
#define se second
#define ll long long
#define pii pair< int, int >
#define MEM(p, v) memset(p, v, sizeof(p))
#define READ(f) freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)
#define S system("pause")
#define R return(0)
#define INF int(1e9)
#define MAX_5 int(1e5+5)
#define MAX_6 int(1e6+6)
#define ll long long
#define tree int h,int l1,int r1
#define left 2*h,l1,(l1+r1)/2
#define right 2*h+1,(l1+r1)/2+1,r1
#define M int(1e9)
using namespace std;
#define ull unsigned long long
#define N int (1e5+5)
ll p[N],siz[N],qve[N],n,ans,w,SUM;
vector<int>v[N];
set<int>st[N];
pair<pii,int>a[N];
int pp(int a)
{
    return ((p[a]==a)?a:(p[a]=pp(p[a])));
}
void un(int a,int b)
{
     int A=pp(a);
     int B=pp(b);

     siz[A]+=siz[B];
     siz[B]=0;
     p[B]=A;
}
int check(int x,int y)
{
     int l=1,r=n,mid,ls=-1;

     while(l<=r)
     {
                mid=l+r;mid/=2;

                if(a[mid].fi.fi==x && a[mid].fi.se==y)ls=a[mid].se;


                if(
                     a[mid].fi.fi<x
                           ||
                    (a[mid].fi.fi==x && a[mid].fi.se<y)
                  )
                                  l=mid+1;else r=mid-1;
     }

     w=ls;
     if(ls==-1)return 0;else return 1;
}
int edge(int x,int y)
{
    return(st[x].count(y));
}
void add(int x,int y)
{
    st[x].insert(y);
    st[y].insert(x);

    v[x].push_back(y);
    v[y].push_back(x);
}
void build(int x,int p=-1)
{
      qve[x]=siz[x];
      for(int i=0;i<v[x].size();i++)
              if(v[x][i]!=p)
                  build(v[x][i],x),
                  qve[x]+=qve[v[x][i]];


}
void go(int x,int p=-1)
{
     ans+=(1LL*qve[x]*(SUM-qve[x]))%M;
      for(int i=0;i<v[x].size();i++)
              if(v[x][i]!=p)
                  go(v[x][i],x);
}
void aloha()
{

    sort(a+1,a+n+1);

    for(int i=1;i<=n;i++)p[i]=i,siz[i]=1;


    for(int i=2;i<=n;i++)
            if(a[i].fi.fi==a[i-1].fi.fi && a[i].fi.se-1==a[i-1].fi.se)
                                  un(a[i-1].se,a[i].se);


    for(int i=1;i<=n;i++)
    {
            if(check(a[i].fi.fi+1,a[i].fi.se))
                 if(!edge(pp(a[i].se),pp(w)))
                      add(pp(a[i].se),pp(w));
    }
     SUM=0;
    for(int i=1;i<=n;i++)SUM+=siz[i];
    build(pp(1));
    go(pp(1));




}
int main(){

    cin>>n;
    for(int i=1;i<=n;i++)cin>>a[i].fi.fi>>a[i].fi.se,a[i].se=i;


    aloha();

    for(int i=1;i<=n;i++)swap(a[i].fi.fi,a[i].fi.se);
    for(int i=1;i<=n;i++)
            v[i].clear(),
            st[i].clear();


    aloha();














    cout<<ans%M<<endl;


    cin>>n;
}