N = int(input())
A = sorted([int(a) for a in input().split()])

def calc(A):
    n = len(A)
    A = A[::-1]
    M = max(a - b for a, b in zip(A, A[1:]))
    ans = 0
    prev = 0
    for k in range(M, A[0] - A[-1] + 1):
        X = [0]
        S = [0]
        j = 0
        for i, a in enumerate(A):
            if i == 0:
                continue
            if i == 1:
                X.append(1)
                S.append(1)
                continue
            while A[j] > a + k:
                j += 1
            X.append((S[-1] - S[j]) % P)
            S.append((S[-1] + X[-1]) % P)
        ans = (ans + (S[-1] - prev) * k) % P
        prev = S[-1]
    return ans * 2 % P

P = 998244353
print(calc(A))