#include <bits/stdc++.h>
using namespace std;
const int MOD = 998244353;
vector<vector<long long> > dp;
vector<long long> ps;
int main() {
  int n, k;
  cin >> n >> k;
  vector<int> a(n + 1);
  int _max = 0;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    _max = max(_max, a[i]);
  }
  sort(a.begin(), a.end());
  long long ans = 0;
  for (int x = 1; x <= (_max / (k - 1)); x++) {
    dp.assign(n + 1, vector<long long>(k + 1, 0));
    ps.assign(n + 1, 0);
    for (int cnt = 1; cnt <= k; cnt++) {
      if (cnt == 1) {
        for (int last = 1; last <= n; last++) {
          dp[last][cnt] = 1;
          ps[last] = (ps[last - 1] + dp[last][cnt]) % MOD;
        }
      } else {
        int l = 1;
        for (int last = 1; last <= n; last++) {
          while (a[l] + x <= a[last]) {
            l++;
          }
          dp[last][cnt] = ps[l - 1];
        }
        for (int last = 1; last <= n; last++) {
          ps[last] = (ps[last - 1] + dp[last][cnt]) % MOD;
        }
      }
    }
    ans = (ans + ps[n]) % MOD;
  }
  cout << ans;
}

### Prompt

Construct a Cpp code solution to the problem outlined:

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;
const int MOD = 998244353;
vector<vector<long long> > dp;
vector<long long> ps;
int main() {
  int n, k;
  cin >> n >> k;
  vector<int> a(n + 1);
  int _max = 0;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    _max = max(_max, a[i]);
  }
  sort(a.begin(), a.end());
  long long ans = 0;
  for (int x = 1; x <= (_max / (k - 1)); x++) {
    dp.assign(n + 1, vector<long long>(k + 1, 0));
    ps.assign(n + 1, 0);
    for (int cnt = 1; cnt <= k; cnt++) {
      if (cnt == 1) {
        for (int last = 1; last <= n; last++) {
          dp[last][cnt] = 1;
          ps[last] = (ps[last - 1] + dp[last][cnt]) % MOD;
        }
      } else {
        int l = 1;
        for (int last = 1; last <= n; last++) {
          while (a[l] + x <= a[last]) {
            l++;
          }
          dp[last][cnt] = ps[l - 1];
        }
        for (int last = 1; last <= n; last++) {
          ps[last] = (ps[last - 1] + dp[last][cnt]) % MOD;
        }
      }
    }
    ans = (ans + ps[n]) % MOD;
  }
  cout << ans;
}

```