#include <bits/stdc++.h>   using namespace std;   long long n, k, x[1010], dp[1010][1010], sm[1010];   long long solve(long long gap) {     dp[0][0] = 1, x[0] = -200000;     for (long long i = 1; i <= k; ++i) {       for (long long j = 0; j <= n; ++j)         sm[j] = j == 0 ? dp[i - 1][j] : (dp[i - 1][j] + sm[j - 1]) % 998244353;       long long pos = 0;       for (long long j = 1; j <= n; ++j) {         while (x[j] - x[pos + 1] >= gap) pos++;         dp[i][j] = sm[pos];       }     }     long long sum = 0;     for (long long i = 1; i <= n; ++i) sum = (sum + dp[k][i]) % 998244353;     return sum;   }   int32_t main() {     cin.tie(0), cout.sync_with_stdio(0);     cin >> n >> k;     for (long long i = 1; i <= n; ++i) cin >> x[i];     sort(x + 1, x + 1 + n);     long long dis = 100000 / (k - 1), pre = solve(1), ans = 0;     for (long long i = 2; i <= dis + 5; ++i) {       long long now = solve(i);       ans = (ans + (pre - now + 998244353) * (i - 1)) % 998244353;       pre = now;     }     cout << ans <<   n ;     return 0;   }   