#include <bits/stdc++.h>
#include <atcoder/fenwicktree>
#include <atcoder/modint>
using namespace atcoder;
using namespace std;
using ll = long long;
using mint = modint998244353;
void naive(vector<int> A) {
	vector<int> B;
	for (int i = 1;i < A.size();i++) B.push_back(A[i]);
	sort(B.begin(), B.end());
	do {
		int d = 0;
		
		for (int i = 0;i < B.size() - 1;i++) d = max(d, abs(B[i + 1] - B[i]));
		for (auto v : B) cout << v << " ";
		cout << " D " << d << endl;
	}while (next_permutation(B.begin(), B.end()));
}
int main() {
	int N;cin >> N;
	int MA = 7;
	vector<int> A(N + 1, MA + 100000);
	for (int i = 1;i <= N;i++) cin >> A[i];
	sort(A.begin(), A.end(), greater<int>());
	mint ans = 0;
	vector<mint> now(N + 1, 0);
	for (int d = 1;d <= MA;d++) {
		vector<mint> dp(N + 1, 0);
		if (A[1] - A[2] <= d) {
			dp[1] = 2;
		} else {
			continue;
		}
		vector<mint> S(N + 1, 0);
		S[1] = 2;

		for (int i = 2;i < N;i++) {
			if (A[i] - A[i + 1] > d) {
				for (int k = 1;k <= N;k++) dp[k] = 0;
				break;
			}
			int ok = i + 1;
			int ng = 0;
			while (ok - ng  > 1) {
				int m = (ok + ng) / 2;
				if (A[m] - A[i + 1] <= d) {
					ok = m;
				} else {
					ng = m;
				}
			}
			dp[i] = S[i - 1] - S[ok - 1];
			S[i] = S[i - 1] + dp[i];
		}
		for (int k = 1;k <= N;k++) ans += mint(d) * mint(dp[k] - now[k]);
		swap(now, dp);
	}
	cout << ans.val() << endl;
}