#include <bits/stdc++.h>
using namespace std;
void debug_out() { cerr << '\n'; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << ' ' << H;
  debug_out(T...);
}
const long long INF = 1e9;
const long long MOD = 998244353;
const int N = 1e3 + 5;
int n, k, A[N], DP[N][N];
int Solve(int x) {
  DP[0][0] = 1;
  for (int i = 1, p = 0; i <= n; i++) {
    while (A[i] - A[p + 1] >= x) p++;
    DP[i][0] = 1;
    for (int j = 1; j <= k; j++) DP[i][j] = (DP[i - 1][j] + DP[p][j - 1]) % MOD;
  }
  return DP[n][k];
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> k;
  int mx = 0;
  for (int i = 1; i <= n; i++) cin >> A[i], mx = max(mx, A[i]);
  sort(A + 1, A + 1 + n);
  int ans = 0;
  for (int i = 1; i * (k - 1) <= mx; i++) ans = (ans + Solve(i)) % MOD;
  cout << ans << '\n';
  return 0;
}

### Prompt

Please create a solution in cpp to 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;
void debug_out() { cerr << '\n'; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << ' ' << H;
  debug_out(T...);
}
const long long INF = 1e9;
const long long MOD = 998244353;
const int N = 1e3 + 5;
int n, k, A[N], DP[N][N];
int Solve(int x) {
  DP[0][0] = 1;
  for (int i = 1, p = 0; i <= n; i++) {
    while (A[i] - A[p + 1] >= x) p++;
    DP[i][0] = 1;
    for (int j = 1; j <= k; j++) DP[i][j] = (DP[i - 1][j] + DP[p][j - 1]) % MOD;
  }
  return DP[n][k];
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> k;
  int mx = 0;
  for (int i = 1; i <= n; i++) cin >> A[i], mx = max(mx, A[i]);
  sort(A + 1, A + 1 + n);
  int ans = 0;
  for (int i = 1; i * (k - 1) <= mx; i++) ans = (ans + Solve(i)) % MOD;
  cout << ans << '\n';
  return 0;
}

```