#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline T read() {
  register T sum = 0;
  register char cc = getchar();
  int sym = 1;
  while (cc != '-' && (cc > '9' || cc < '0')) cc = getchar();
  if (cc == '-') sym = -1, cc = getchar();
  sum = sum * 10 + cc - '0';
  cc = getchar();
  while (cc >= '0' && cc <= '9') sum = sum * 10 + cc - '0', cc = getchar();
  return sym * sum;
}
template <typename T>
inline T read(T &a) {
  a = read<T>();
  return a;
}
template <typename T, typename... Others>
inline void read(T &a, Others &...b) {
  a = read(a);
  read(b...);
}
struct Data {
  int x, y, p;
} a[200010];
int n, l[200010], r[200010], t[200010];
long long ans1, ans2;
int lowbit(int x) { return x & -x; }
void change(int x, int y) {
  for (int i = x; i <= n << 1; i += lowbit(i)) t[i] += y;
}
int query(int x) {
  int res = 0;
  for (int i = x; i; i -= lowbit(i)) res += t[i];
  return res;
}
bool cmp1(const Data &a, const Data &b) { return a.x < b.x; }
bool cmp2(const Data &a, const Data &b) { return a.y > b.y; }
int main() {
  read(n);
  for (int i = 1; i <= n; i++) {
    read(a[i].x, a[i].y);
    if (a[i].x > a[i].y) swap(a[i].x, a[i].y);
    a[i].p = i;
  }
  sort(a + 1, a + 1 + n, cmp1);
  for (int i = 1; i <= n; i++) {
    l[a[i].p] += query(a[i].x) + query(n << 1) - query(a[i].y);
    change(a[i].y, 1);
  }
  memset(t + 1, 0, sizeof(int) * (n << 1));
  for (int i = n; i >= 1; i--) {
    r[a[i].p] = query(a[i].y);
    change(a[i].y, 1);
  }
  memset(t + 1, 0, sizeof(int) * (n << 1));
  sort(a + 1, a + 1 + n, cmp2);
  for (int i = 1; i <= n; i++) {
    l[a[i].p] += query(n << 1) - query(a[i].y);
    change(a[i].x, 1);
  }
  ans1 = 1ll * n * (n - 1) * (n - 2) / 6;
  for (int i = 1; i <= n; i++) {
    ans1 -= 1ll * l[i] * r[i];
    ans2 += 1ll * (l[i] + r[i]) * (n - l[i] - r[i] - 1);
  }
  printf("%lld\n", ans1 - ans2 / 2);
  return 0;
}
