#include <bits/stdc++.h>
using namespace std;
inline void solve();
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  solve();
}
void solve() {
  long long n, k;
  cin >> n >> k;
  vector<long long> a(n);
  for (long long i = 0; i < n; i++) cin >> a[i];
  sort(a.begin(), a.end());
  long long ans = 0;
  for (long long d = 1; d <= a[n - 1] / (k - 1); d++) {
    vector<long long> ndp(n), dp(n, 1);
    for (long long i = 2; i <= k; i++) {
      long long l = 0;
      long long sum = 0;
      for (long long j = 1; j < n; j++) {
        while (a[l] + d <= a[j]) {
          sum += dp[l];
          sum %= 998244353;
          l++;
        }
        ndp[j] = sum;
      }
      swap(ndp, dp);
      for (long long j = 0; j < n; j++) ndp[j] = 0;
    }
    for (long long j = 0; j < n; j++) {
      ans += dp[j];
      ans %= 998244353;
    }
  }
  cout << ans;
}

### Prompt

In CPP, your task is to solve the following problem:

Let's call beauty of an array b_1, b_2, …, b_n (n > 1) — min_{1 ≤ i < j ≤ n} |b_i - b_j|.

You're given an array a_1, a_2, … a_n and a number k. Calculate the sum of beauty over all subsequences of the array of length exactly k. As this number can be very large, output it modulo 998244353.

A sequence a is a subsequence of an array b if a can be obtained from b by deletion of several (possibly, zero or all) elements.

Input

The first line contains integers n, k (2 ≤ k ≤ n ≤ 1000).

The second line contains n integers a_1, a_2, …, a_n (0 ≤ a_i ≤ 10^5).

Output

Output one integer — the sum of beauty over all subsequences of the array of length exactly k. As this number can be very large, output it modulo 998244353.

Examples

Input


4 3
1 7 3 5


Output


8

Input


5 5
1 10 100 1000 10000


Output


9

Note

In the first example, there are 4 subsequences of length 3 — [1, 7, 3], [1, 3, 5], [7, 3, 5], [1, 7, 5], each of which has beauty 2, so answer is 8.

In the second example, there is only one subsequence of length 5 — the whole array, which has the beauty equal to |10-1| = 9.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
inline void solve();
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  solve();
}
void solve() {
  long long n, k;
  cin >> n >> k;
  vector<long long> a(n);
  for (long long i = 0; i < n; i++) cin >> a[i];
  sort(a.begin(), a.end());
  long long ans = 0;
  for (long long d = 1; d <= a[n - 1] / (k - 1); d++) {
    vector<long long> ndp(n), dp(n, 1);
    for (long long i = 2; i <= k; i++) {
      long long l = 0;
      long long sum = 0;
      for (long long j = 1; j < n; j++) {
        while (a[l] + d <= a[j]) {
          sum += dp[l];
          sum %= 998244353;
          l++;
        }
        ndp[j] = sum;
      }
      swap(ndp, dp);
      for (long long j = 0; j < n; j++) ndp[j] = 0;
    }
    for (long long j = 0; j < n; j++) {
      ans += dp[j];
      ans %= 998244353;
    }
  }
  cout << ans;
}

```