#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>
#define pb push_back
#define mp make_pair
#define taskname "A"
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
typedef tree <int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
const int maxn = 1e5 + 5;
int n;
vector<ii> a;
ll ans = 0;
int gr[maxn];
int sz[maxn];
set<int> adj[maxn];
bool vis[maxn];
void dfs(int u){
vis[u] = 1;
for(auto c : adj[u]){
if(!vis[c]){
dfs(c);
sz[u] += sz[c];
}
}
ans += 1ll * sz[u] * (n - sz[u]);
}
void solve(){
for(int i = 0 ; i < n ; ++i)adj[i].clear();
sort(a.begin(),a.end());
int m = 0;
for(int i = 0 ; i < n ; ){
int j = i + 1;
gr[i] = m;
while(j < n && a[j] == mp(a[j - 1].first , a[j - 1].second + 1))gr[j++] = m;
sz[m] = j - i;
i = j;
++m;
}
for(int i = 0 , j = 0 ; i < n ; ++i){
while(j < n && a[j] < mp(a[i].first - 1 , a[i].second))++j;
if(j < n && a[j] == mp(a[i].first - 1 , a[i].second)){
adj[gr[i]].insert(gr[j]);
adj[gr[j]].insert(gr[i]);
// cout << gr[i] << " " << gr[j] << endl;
}
}
memset(vis,0,sizeof vis);
dfs(0);
}
int DistanceSum(int N, int *X, int *Y) {
n = N;
for(int i = 0 ; i < n ; ++i)a.pb(mp(X[i],Y[i]));
solve();
for(int i = 0 ; i < n ; ++i)swap(a[i].first,a[i].second);
solve();
return ans % (int)1e9;
}
#ifdef LOCAL
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#define inbuf_len 1 << 16
#define outbuf_len 1 << 16
int DistanceSum(int N, int *X, int *Y);
int main() {
int tmp;
/* Set input and output buffering */
freopen("A.INP","r",stdin);
freopen("A.OUT","w",stdout);
int N, i;
tmp = scanf("%d", &N);
assert(tmp == 1);
int *sq_x, *sq_y;
sq_x = (int*) malloc(N * sizeof(int));
sq_y = (int*) malloc(N * sizeof(int));
for (i = 0; i < N; i++) {
tmp = scanf("%d %d", &sq_x[i], &sq_y[i]);
assert(tmp == 2);
}
int ds = DistanceSum(N, sq_x, sq_y);
printf("%d\n", ds);
return 0;
}
#endif // LOCAL
