#include <bits/stdc++.h>
using namespace std;
void fun() {}
long long int md = 998244353;
long long int __gcd(long long int a, long long int b) {
  if (b == 0) return a;
  return __gcd(b, a % b);
}
long long int poww(long long int a, long long int b, long long int md) {
  if (b < 0) return 0;
  if (a == 0) return 0;
  long long int res = 1;
  while (b) {
    if (b & 1) {
      res = (1ll * res * a) % md;
    }
    a = (1ll * a * a) % md;
    b >>= 1;
  }
  return res;
}
long long int poww(long long int a, long long int b) {
  if (b < 0) return 0;
  if (a == 0) return 0;
  long long int res = 1;
  while (b) {
    if (b & 1) {
      res = (1ll * res * a);
    }
    a = (1ll * a * a);
    b >>= 1;
  }
  return res;
}
void ainp(long long int arr[], long long int n) {
  for (long long int i = 1; i <= n; i++) cin >> arr[i];
}
void disp(long long int arr[], long long int n) {
  for (long long int i = 1; i <= n; i++) cout << arr[i] << " ";
  cout << "\n";
}
void dispv(vector<long long int> &v) {
  for (long long int i = 0; i < v.size(); i++) cout << v[i] << " ";
  cout << "\n";
}
long long int divide(long long int a, long long int b, long long int md) {
  long long int rr = a * (poww(b, md - 2, md));
  rr %= md;
  return rr;
}
const long long int size = 3e5 + 5;
long long int fact[size], invfact[size];
long long int n, k, l, r, ans;
vector<pair<long long int, pair<long long int, long long int> > > moment;
void calc() {
  fact[0] = 1;
  for (long long int i = 1; i <= n; i++) fact[i] = fact[i - 1] * i % md;
  invfact[n] = divide(1, fact[n], md);
  for (long long int i = n - 1; i >= 0; i--)
    invfact[i] = invfact[i + 1] * (i + 1) % md;
}
long long int ncr(long long int n, long long int r) {
  if (n < r) return 0;
  return fact[n] * invfact[r] % md * invfact[n - r] % md;
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  fun();
  cin >> n >> k;
  calc();
  for (long long int i = 1; i <= n; i++) {
    cin >> l >> r;
    moment.push_back(make_pair(l, make_pair(0, i)));
    moment.push_back(make_pair(r, make_pair(1, i)));
  }
  sort(moment.begin(), moment.end());
  set<long long int> onn;
  for (long long int i = 0; i < moment.size(); i++) {
    if (moment[i].second.first == 0) {
      ans = (ans + ncr(onn.size(), k - 1)) % md;
      onn.insert(moment[i].second.second);
    } else {
      onn.erase(moment[i].second.second);
    }
  }
  cout << ans << "\n";
  return 0;
}
