#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long int ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<vvvl> vvvvl;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<vvvb> vvvvb;
typedef pair<ll,ll> pl;
typedef pair<ll,pl> ppl;
typedef pair<ll,ppl> pppl;
typedef pair<ll,pppl> pppppl;
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(a) begin(a),end(a)
#define sz(a) (int)(a).size()
#define F first
#define S second
#define bs(A,x) binary_search(all(A),x)
#define lb(A,x) (ll)(lower_bound(all(A),x)-A.begin())
#define ub(A,x) (ll)(upper_bound(all(A),x)-A.begin())
#define cou(A,x) (ll)(upper_bound(all(A),x)-lower_bound(all(A),x))
template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}
//*
using mint=modint998244353;
const ll mod=998244353;
//*/
/*
using mint=modint1000000007;
const ll mod=1000000007;
//*/
//using mint=modint;
//*
typedef vector<mint> vm;
typedef vector<vm> vvm;
typedef vector<vvm> vvvm;
typedef vector<vvvm> vvvvm;
ostream&operator<<(ostream&os,mint a){os<<a.val();return os;}
istream&operator>>(istream&is,mint&a){int x;is>>x;a=mint(x);return is;}
//*/
template<typename T1,typename T2>ostream&operator<<(ostream&os,pair<T1,T2>p){os<<p.F<<" "<<p.S;return os;}
template<typename T1,typename T2>istream&operator>>(istream&is,pair<T1,T2>&p){is>>p.F>>p.S;return is;}
template<typename T>ostream&operator<<(ostream&os,vector<T>v){rep(i,0,sz(v))os<<v[i]<<(i+1!=sz(v)?" ":"");return os;}
template<typename T>istream&operator>>(istream&is,vector<T>&v){for(T&in:v)is>>in;return is;}
template<class S,S(*op)(S,S),S(*e)()>
struct kDTree{
    using ll=long long;
    using pi=pair<ll,ll>;
    using Iter=typename vector<pair<pi,S>>::iterator;
    kDTree *l=nullptr,*r=nullptr;
    ll xmin=INT_MAX,xmax=INT_MIN,ymin=INT_MAX,ymax=INT_MIN,size=0;
    S product;
    kDTree(Iter begin,Iter end,bool divx=true){
        product=e();
        for(auto p=begin;p!=end;p++){
            auto[c,v]=*p;
            product=op(product,v);
            chmin(xmin,c.first);
            chmax(xmax,c.first);
            chmin(ymin,c.second);
            chmax(ymax,c.second);
        }
        size=int(end-begin);
        if(size<=1)return;
        auto cen=begin+size/2;
        if(divx){
            nth_element(begin,cen,end,[](pair<pi,S>a,pair<pi,S>b){return a.first.first<b.first.first;});
        }
        else{
            nth_element(begin,cen,end,[](pair<pi,S>a,pair<pi,S>b){return a.first.second<b.first.second;});
        }
        l=new kDTree(begin,cen,!divx);
        r=new kDTree(cen,end,!divx);
    }
    void set(ll x,ll y,S v){
        if(x<xmin||xmax<x||y<ymin||ymax<y)return;
        if(size==1){product=v;return;}
        l->set(x,y,v);r->set(x,y,v);
        product=op(l->product,r->product);
    }
    S prod(ll x1,ll x2,ll y1,ll y2){
        if(x2<xmin||xmax<x1||y2<ymin||ymax<y1)return e();
        if(x1<=xmin&&xmax<=x2&&y1<=ymin&&ymax<=y2)return product;
        return op(l->prod(x1,x2,y1,y2),r->prod(x1,x2,y1,y2));
    }
};
ll op(ll a,ll b){return a+b;}
ll e(){return 0;}
int main(){
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);
  ll N;cin>>N;
  vector<pl>A(N);
  cin>>A;
  vector<pair<pl,ll>>T(N);
  rep(i,0,N)T[i]=make_pair(A[i],0);
  kDTree<ll,op,e>tr(all(T));
  ll ans=0;
  rep(i,0,N){
  	ans+=tr.prod(0,A[i].F,A[i].S,2e6);
  	tr.set(A[i].F,A[i].S,1);
  }
  cout<<ans<<endl;
  return 0;
}