#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,auto op,auto e>
struct segtree_2d_sparse_with_ACL{
    private:
    size_t H,W;
    vector<segtree<S,op,e>>seg;
    vector<vector<int>>E;
    int id(int h,int w){
        if(!binary_search(E[h].begin(),E[h].end(),w))return -1;
        return lower_bound(E[h].begin(),E[h].end(),w)-E[h].begin();
    }
    public:
    segtree_2d_sparse_with_ACL(size_t _H,size_t _W,vector<pair<int,int>>query){init(_H,_W,query);}
    void init(size_t _H,size_t _W,vector<pair<int,int>>query){
        H=W=1;
        while(H<_H)H<<=1;
        while(W<_W)W<<=1;
        E.resize(2*H);
        seg.resize(2*H);
        for(auto[h,w]:query){
            assert(0<=h&&h<H&&0<=w&&w<W);
            E[h+H].emplace_back(w);
        }
        for(int i=2*H-1;i;i--){
            sort(E[i].begin(),E[i].end());
            E[i].erase(unique(E[i].begin(),E[i].end()),E[i].end());
            seg[i]=segtree<S,op,e>(E[i].size());
            if(i)for(int j:E[i])E[i>>1].emplace_back(j);
        }
    }
    void set(int h,int w,S x){
        assert(0<=h&&h<H&&0<=w&&w<W);
        h+=H;
        assert(id(h,w)!=-1);
        seg[h].set(id(h,w),x);
        while(h>1){
            if(id(h^1,w)!=-1)x=op(x,seg[h^1].get(id(h^1,w)));
            h>>=1;
            seg[h].set(id(h,w),x);
        }
    }
    S get(int h,int w){
        assert(0<=h&&h<H&&0<=w&&w<W);
        h+=H;
        if(id(h,w)==-1)return e();
        return seg[h].get(id(h,w));
    }
    S prod(int h1,int h2,int w1,int w2){
        assert(0<=h1&&h1<=h2&&h2<=H&&0<=w1&&w1<=w2&&w2<=W);
        h1+=H;h2+=H;
        S res=e();
        while(h1<h2){
            if(h1&1)res=op(res,seg[h1].prod(lower_bound(E[h1].begin(),E[h1].end(),w1)-E[h1].begin(),lower_bound(E[h1].begin(),E[h1].end(),w2)-E[h1].begin())),h1++;
            if(h2&1)h2--,res=op(res,seg[h2].prod(lower_bound(E[h2].begin(),E[h2].end(),w1)-E[h2].begin(),lower_bound(E[h2].begin(),E[h2].end(),w2)-E[h2].begin()));
            h1>>=1;
            h2>>=1;
        }
        return res;
    }
};
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<int,int>>query(N);
  rep(i,0,N)query[i]=make_pair(i,A[i].second);
  segtree_2d_sparse_with_ACL<ll,op,e>seg(1000010,1000010,query);
  vl I(N);
  iota(all(I),0);
  sort(all(I),[&](ll a,ll b){return A[a]<A[b];});
  ll ans=0;
  rrep(_,0,N){
    ll i=I[_];
    ans+=seg.prod(i+1,N,0,A[i].second);
    seg.set(i,A[i].second,1);
  }
  cout<<ans<<endl;
  return 0;
}