// modified: https://ei1333.github.io/library/test/verify/yosupo-point-add-rectangle-sum-2.test.cpp

#line 1 "test/verify/yosupo-point-add-rectangle-sum-2.test.cpp"
// competitive-verifier: PROBLEM https://judge.yosupo.jp/problem/point_add_rectangle_sum

#line 1 "template/template.hpp"
#include <bits/stdc++.h>
#if __has_include(<atcoder/all>)
#include <atcoder/all>
#endif

using namespace std;

using int64 = long long;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;

template <typename T1, typename T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T1, typename T2>
istream& operator>>(istream& is, pair<T1, T2>& p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template <typename T>
istream& operator>>(istream& is, vector<T>& v) {
  for (T& in : v) is >> in;
  return is;
}

template <typename T1, typename T2>
inline bool chmax(T1& a, T2 b) {
  return a < b && (a = b, true);
}

template <typename T1, typename T2>
inline bool chmin(T1& a, T2 b) {
  return a > b && (a = b, true);
}

template <typename T = int64>
vector<T> make_v(size_t a) {
  return vector<T>(a);
}

template <typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

template <typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type fill_v(T& t, const V& v) {
  t = v;
}

template <typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type fill_v(T& t, const V& v) {
  for (auto& e : t) fill_v(e, v);
}

template <typename F>
struct FixPoint : F {
  explicit FixPoint(F&& f) : F(std::forward<F>(f)) {}

  template <typename... Args>
  decltype(auto) operator()(Args&&... args) const {
    return F::operator()(*this, std::forward<Args>(args)...);
  }
};

template <typename F>
inline decltype(auto) MFP(F&& f) {
  return FixPoint<F>{std::forward<F>(f)};
}
#line 4 "test/verify/yosupo-point-add-rectangle-sum-2.test.cpp"

#line 1 "structure/others/abstract-binary-indexed-tree.hpp"
/**
 * @brief Abstract Binary Indexed Tree(抽象化BIT)
 */
template <typename T, typename F>
struct AbstractBinaryIndexedTree {
 private:
  int n;
  vector<T> data;
  const F f;
  const T e;

 public:
  AbstractBinaryIndexedTree() = default;

  explicit AbstractBinaryIndexedTree(int n, const F f, const T& e)
      : n(n), f(f), e(e) {
    data.assign(n + 1, e);
  }

  explicit AbstractBinaryIndexedTree(const vector<T>& v, const F f, const T& e)
      : AbstractBinaryIndexedTree((int)v.size(), f, e) {
    build(v);
  }

  void build(const vector<T>& v) {
    assert(n == (int)v.size());
    for (int i = 1; i <= n; i++) data[i] = v[i - 1];
    for (int i = 1; i <= n; i++) {
      int j = i + (i & -i);
      if (j <= n) data[j] = f(data[j], data[i]);
    }
  }

  void apply(int k, const T& x) {
    for (++k; k <= n; k += k & -k) data[k] = f(data[k], x);
  }

  T prod(int r) const {
    T ret{e};
    for (; r > 0; r -= r & -r) ret = f(ret, data[r]);
    return ret;
  }
};

template <typename T, typename F>
AbstractBinaryIndexedTree<T, F> get_abstract_binary_indexed_tree(int n,
                                                                 const F& f,
                                                                 const T& e) {
  return AbstractBinaryIndexedTree{n, f, e};
}

template <typename T, typename F>
AbstractBinaryIndexedTree<T, F> get_abstract_binary_indexed_tree(
    const vector<T>& v, const F& f, const T& e) {
  return AbstractBinaryIndexedTree{v, f, e};
}
#line 2 "structure/others/abstract-2d-binary-indexed-tree-compressed.hpp"

/**
 * @brief Abstract 2D Binary Indexed Tree Compressed(抽象化2次元座圧BIT)
 */
template <typename T, typename F>
struct Abstract2DBinaryIndexedTreeCompressed {
 private:
  int n;
  vector<AbstractBinaryIndexedTree<T, F> > data;
  const F f;
  const T e;
  vector<int> hs;
  vector<vector<int> > beet;

 public:
  Abstract2DBinaryIndexedTreeCompressed(const vector<int>& hs, const F f,
                                        const T& e)
      : n((int)hs.size()), hs(hs), f(f), e(e) {
    vector<int> ord(n);
    iota(begin(ord), end(ord), 0);
    sort(begin(ord), end(ord), [&](int a, int b) { return hs[a] < hs[b]; });
    beet.resize(n + 1);
    for (auto&& i : ord) {
      for (int k = i + 1; k <= n; k += k & -k) {
        beet[k].emplace_back(hs[i]);
      }
    }
    data.reserve(n + 1);
    for (int k = 0; k <= n; k++) {
      beet[k].erase(unique(begin(beet[k]), end(beet[k])), end(beet[k]));
      data.emplace_back((int)beet[k].size(), f, e);
    }
  }

  void apply(int k1, const T& x) {
    int k2 = hs[k1];
    for (++k1; k1 <= n; k1 += k1 & -k1) {
      int p = lower_bound(begin(beet[k1]), end(beet[k1]), k2) - begin(beet[k1]);
      data[k1].apply(p, x);
    }
  }

  T prod(int r1, int r2) const {
    T ret{e};
    for (; r1 > 0; r1 -= r1 & -r1) {
      int p = lower_bound(begin(beet[r1]), end(beet[r1]), r2) - begin(beet[r1]);
      ret = f(ret, data[r1].prod(p));
    }
    return ret;
  }
};

template <typename T, typename F>
Abstract2DBinaryIndexedTreeCompressed<T, F>
get_abstract_2d_binary_indexed_tree_compressed(const vector<int>& hs,
                                               const F& f, const T& e) {
  return Abstract2DBinaryIndexedTreeCompressed{hs, f, e};
}
#line 6 "test/verify/yosupo-point-add-rectangle-sum-2.test.cpp"

#line 1 "other/scanner.hpp"
/**
 * @brief Scanner(高速入力)
 */
struct Scanner {
 public:
  explicit Scanner(FILE* fp) : fp(fp) {}

  template <typename T, typename... E>
  void read(T& t, E&... e) {
    read_single(t);
    read(e...);
  }

 private:
  static constexpr size_t line_size = 1 << 16;
  static constexpr size_t int_digits = 20;
  char line[line_size + 1] = {};
  FILE* fp = nullptr;
  char* st = line;
  char* ed = line;

  void read() {}

  static inline bool is_space(char c) { return c <= ' '; }

  void reread() {
    ptrdiff_t len = ed - st;
    memmove(line, st, len);
    char* tmp = line + len;
    ed = tmp + fread(tmp, 1, line_size - len, fp);
    *ed = 0;
    st = line;
  }

  void skip_space() {
    while (true) {
      if (st == ed) reread();
      while (*st && is_space(*st)) ++st;
      if (st != ed) return;
    }
  }

  template <typename T, enable_if_t<is_integral<T>::value, int> = 0>
  void read_single(T& s) {
    skip_space();
    if (st + int_digits >= ed) reread();
    bool neg = false;
    if (is_signed<T>::value && *st == '-') {
      neg = true;
      ++st;
    }
    typename make_unsigned<T>::type y = *st++ - '0';
    while (*st >= '0') {
      y = 10 * y + *st++ - '0';
    }
    s = (neg ? -y : y);
  }

  template <typename T, enable_if_t<is_same<T, string>::value, int> = 0>
  void read_single(T& s) {
    s = "";
    skip_space();
    while (true) {
      char* base = st;
      while (*st && !is_space(*st)) ++st;
      s += string(base, st);
      if (st != ed) return;
      reread();
    }
  }

  template <typename T>
  void read_single(vector<T>& s) {
    for (auto& d : s) read(d);
  }
};
#line 1 "other/printer.hpp"
/**
 * @brief Printer(高速出力)
 */
struct Printer {
 public:
  explicit Printer(FILE* fp) : fp(fp) {}

  ~Printer() { flush(); }

  template <bool f = false, typename T, typename... E>
  void write(const T& t, const E&... e) {
    if (f) write_single(' ');
    write_single(t);
    write<true>(e...);
  }

  template <typename... T>
  void writeln(const T&... t) {
    write(t...);
    write_single('\n');
  }

  void flush() {
    fwrite(line, 1, st - line, fp);
    st = line;
  }

 private:
  FILE* fp = nullptr;
  static constexpr size_t line_size = 1 << 16;
  static constexpr size_t int_digits = 20;
  char line[line_size + 1] = {};
  char* st = line;

  template <bool f = false>
  void write() {}

  void write_single(const char& t) {
    if (st + 1 >= line + line_size) flush();
    *st++ = t;
  }

  template <typename T, enable_if_t<is_integral<T>::value, int> = 0>
  void write_single(T s) {
    if (st + int_digits >= line + line_size) flush();
    st += to_chars(st, st + int_digits, s).ptr - st;
  }

  void write_single(const string& s) {
    for (auto& c : s) write_single(c);
  }

  void write_single(const char* s) {
    while (*s != 0) write_single(*s++);
  }

  template <typename T>
  void write_single(const vector<T>& s) {
    for (size_t i = 0; i < s.size(); i++) {
      if (i) write_single(' ');
      write_single(s[i]);
    }
  }
};
#line 9 "test/verify/yosupo-point-add-rectangle-sum-2.test.cpp"

int main() {
  Scanner in(stdin);
  Printer out(stdout);
  int N;//, Q;
  in.read(N);//, Q);
  vector< int > X(N), Y(N);//, W(N);
  vector< pair< int, int > > ps(N);
  for(int i = 0; i < N; i++) {
    in.read(X[i], Y[i]);//, W[i]);
    Y[i] = 1000000 - Y[i];
    ps[i] = {X[i], Y[i]};
  }
  // vector< int > A(Q), B(Q), C(Q), D(Q), E(Q);
  // for(int i = 0; i < Q; i++) {
  //   in.read(A[i], B[i], C[i], D[i]);
  //   if(A[i] == 0) ps.emplace_back(B[i], C[i]);
  //   else in.read(E[i]);
  // }
  sort(begin(ps), end(ps));
  ps.erase(unique(begin(ps), end(ps)), end(ps));
  vector< int > H(ps.size());
  for(int i = 0; i < N; i++) {
    X[i] = lower_bound(begin(ps), end(ps), make_pair(X[i], Y[i])) - begin(ps);
  }
  // for(int i = 0; i < Q; i++) {
  //   if(A[i] == 0) {
  //     B[i] = lower_bound(begin(ps), end(ps), make_pair(B[i], C[i])) - begin(ps);
  //   } else {
  //     B[i] = lower_bound(begin(ps), end(ps), make_pair(B[i], -inf)) - begin(ps);
  //     D[i] = lower_bound(begin(ps), end(ps), make_pair(D[i], -inf)) - begin(ps);
  //   }
  // }
  for(int i = 0; i < (int) ps.size(); i++) {
    H[i] = ps[i].second;
  }
  auto f = [](int64 a, int64 b) { return a + b; };
  auto bit = get_abstract_2d_binary_indexed_tree_compressed(H, f, 0LL);
  long long ans = 0;
  for(int i = 0; i < N; i++) {
  // }
  // for(int i = 0; i < Q; i++) {
    ans += bit.prod(X[i], Y[i]);
    bit.apply(X[i], 1);
  }
  out.writeln(ans);
}