#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
inline void smin(T &a, U b) {
  if (a > b) a = b;
}
template <typename T, typename U>
inline void smax(T &a, U b) {
  if (a < b) a = b;
}
template <class T>
inline void gn(T &first) {
  char c, sg = 0;
  while (c = getchar(), (c > '9' || c < '0') && c != '-')
    ;
  for ((c == '-' ? sg = 1, c = getchar() : 0), first = 0; c >= '0' && c <= '9';
       c = getchar())
    first = (first << 1) + (first << 3) + c - '0';
  if (sg) first = -first;
}
template <class T, class T1>
inline void gn(T &first, T1 &second) {
  gn(first);
  gn(second);
}
template <class T, class T1, class T2>
inline void gn(T &first, T1 &second, T2 &z) {
  gn(first);
  gn(second);
  gn(z);
}
template <class T>
inline void print(T first) {
  if (first < 0) {
    putchar('-');
    return print(-first);
  }
  if (first < 10) {
    putchar('0' + first);
    return;
  }
  print(first / 10);
  putchar(first % 10 + '0');
}
template <class T>
inline void printsp(T first) {
  print(first);
  putchar(' ');
}
template <class T>
inline void println(T first) {
  print(first);
  putchar('\n');
}
template <class T, class U>
inline void print(T first, U second) {
  printsp(first);
  println(second);
}
template <class T, class U, class V>
inline void print(T first, U second, V z) {
  printsp(first);
  printsp(second);
  println(z);
}
int power(int a, int b, int m, int ans = 1) {
  for (; b; b >>= 1, a = 1LL * a * a % m)
    if (b & 1) ans = 1LL * ans * a % m;
  return ans;
}
int in[300011];
vector<int> adj[300011];
pair<int, int> q[300011];
long long ans;
int tmp[300011];
int arr[300011];
int nn;
int vst[300011];
int runs;
int main() {
  int n, p;
  cin >> n >> p;
  for (int i = 1; i <= n; i++) {
    int u, v;
    gn(u, v);
    in[u]++;
    in[v]++;
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  for (int i = 1; i <= n; i++) q[i] = pair<int, int>(in[i], i);
  sort(q + 1, q + n + 1);
  for (int i = 1; i <= n; i++) {
    int pos = lower_bound(q + 1, q + n + 1, pair<int, int>(p - in[i], 0)) - q;
    ans += n - pos + 1;
    nn = 0;
    runs++;
    for (int j = 0; j < ((int)adj[i].size()); j++) {
      int u = adj[i][j];
      if (vst[u] == runs) {
        tmp[u]--;
        continue;
      }
      vst[u] = runs;
      arr[nn++] = u;
      tmp[u] = in[u] - 1;
    }
    for (int j = 0; j < nn; j++) {
      int u = arr[j];
      if (in[u] + in[i] >= p and tmp[u] + in[i] < p) ans--;
    }
    if (in[i] + in[i] >= p) ans--;
  }
  println(ans >> 1);
  return 0;
}
