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 % MOD)

ans = 0
for i in range(N - 1):
    ans = (ans * (i+1) + (x[-1] - x[i]) * kaijo[i]) % MOD

print(ans)