MOD = 10 ** 9 + 7
N = int(input())
x = list(map(int, input().split()))
x.sort()
 
kaijo = [1]
for i in range(1, N):
    kaijo.append(kaijo[-1] * i)
 
ans = 0
for i in range(N - 1):
    ans = (ans * (i + 1) + (x[-1] - x[i]) * kaijo[i]) % MOD
 
print(ans)