#include <bits/stdc++.h>
#define ll long long
#define db long double
#define II pair <ll,ll>
#define III pair <ll,II>
#define IV pair <vector <int>,vector <int> >
#define fst first
#define snd second
#define BIT(x,i) ((x>>i)&1)
#define pi acos(-1)
#define to_radian(x) (x*pi/180.0)
#define to_degree(x) (x*180.0/pi)
#define Log(x) (31-__builtin_clz((int)x))
#define LogLL(x) (63-__builtin_clzll((ll)x))
#define N 100005
using namespace std;
struct pt { int x,y,pos; } a[N];
struct International_Olympiad_in_Informatics
{
vector <int> a[N];
ll n,i,j,step,u,v,mod=1e9,sz[N],res,node[N];
void DFS(int u,int p)
{
for(int v:a[u])
if(v!=p)
{
DFS(v,u);
sz[u]+=sz[v];
res=(res+sz[v]*(n-sz[v]))%mod;
}
}
int Work(int _n,pt cell[])
{
n=_n;
res=0;
for(step=0;step<=1;step++)
{
map <II,int> num;
memset(sz,0,sizeof(sz));
sort(cell+1,cell+n+1,[&](pt a,pt b){ return (a.x<b.x || (a.x==b.x && a.y<b.y)); });
for(i=1;i<=n;i++)
{
num[make_pair(cell[i].x,cell[i].y)]=i;
a[i].clear();
}
int u=1;
for(i=1;i<=n;i++)
{
node[i]=u;
if(i==n || cell[i+1].x>cell[i].x || (cell[i+1].x==cell[i].x && cell[i].y+1<cell[i+1].y))
{
set <int> s;
for(j=i;node[j]==u;j--)
{
s.insert(node[num[make_pair(cell[j].x-1,cell[j].y)]]);
sz[u]++;
}
for(int v:s)
if(v>0)
{
a[u].push_back(v),a[v].push_back(u);
}
u++;
}
}
DFS(1,0);
for(i=1;i<=n;i++) swap(cell[i].x,cell[i].y);
}
return res;
}
} IOI;
int x[N],y[N],n,i;
int DistanceSum(int n,int _x[], int _y[])
{
for(int i=n;i>=1;i--) a[i].x=_x[i-1],a[i].y=_y[i-1];
return IOI.Work(n,a);
}
/*
int main()
{
freopen("city.inp","r",stdin);
freopen("city.out","w",stdout);
cin>>n;
for(i=0;i<n;i++) cin>>x[i]>>y[i];
cout<<DistanceSum(n,x,y);
}
*/
