Problem:
Score : 500 points

Problem Statement

On a two-dimensional plane, there are m lines drawn parallel to the x axis, and n lines drawn parallel to the y axis.
Among the lines parallel to the x axis, the i-th from the bottom is represented by y = y_i.
Similarly, among the lines parallel to the y axis, the i-th from the left is represented by x = x_i.

For every rectangle that is formed by these lines, find its area, and print the total area modulo 10^9+7.

That is, for every quadruple (i,j,k,l) satisfying 1\leq i < j\leq n and 1\leq k < l\leq m, find the area of the rectangle formed by the lines x=x_i, x=x_j, y=y_k and y=y_l, and print the sum of these areas modulo 10^9+7.

Constraints

2 \leq n,m \leq 10^5

-10^9 \leq x_1 < ... < x_n \leq 10^9

-10^9 \leq y_1 < ... < y_m \leq 10^9

x_i and y_i are integers.

Input

Input is given from Standard Input in the following format:

n m
x_1 x_2 ... x_n
y_1 y_2 ... y_m

Output

Print the total area of the rectangles, modulo 10^9+7.

Sample Input 1

3 3
1 3 4
1 3 6

Sample Output 1

60

The following figure illustrates this input:

The total area of the nine rectangles A, B, ..., I shown in the following figure, is 60.

Sample Input 2

6 5
-790013317 -192321079 95834122 418379342 586260100 802780784
-253230108 193944314 363756450 712662868 735867677

Sample Output 2

835067060

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <algorithm>
#include <string>
#include <map>
#include <math.h>
#include <set>

using namespace std;
typedef long long  ll;
#define rep(i,s,n)for(ll i=s;i<n;i++)
#define repe(i,s,n)for(ll i=s;i<=n;i++)

static const double PI = 3.1415926535897932384626433;

///////////////////////////
////Prime Creator//////////
///////////////////////////
//bool Prime[100001] = {};
//void createPrime() {
//	ll n = 100001;
//	rep(i, 0, n) Prime[i] = true;
//	Prime[0] = false;
//	Prime[1] = false;
//	rep(i, 2, n) {
//		if (Prime[i]) {
//			rep(j, 2, n) {
//				if (j*i >= n)break;
//				Prime[j*i] = false;
//			}
//		}
//	}
//}
///////////////////////////
///////////////////////////

///////////////////////////
////Warshal Floyid/////////
///////////////////////////
////initialize`
////rep(i, 0, N)rep(j, 0, N) wf[i][j] = 1 << 29;
//static const ll WF_MAX = 300;
//ll wf[WF_MAX][WF_MAX];
//void WarshalFloyid(int size) {
//	rep(k, 0, size)rep(i, 0, size)rep(j, 0, size)wf[i][j] = min(wf[i][j], wf[i][k] + wf[k][j]);
//}

ll x[100001] = {};
ll y[100001] = {};
int main() {
	ll n, m; cin >> n >> m;
	repe(i, 1, n)cin >> x[i];
	repe(i, 1, m)cin >> y[i];
	//sort(x + 1, x + n);
	//sort(y + 1, y + n);
	ll MOD = 1000000007;
	ll X = 0;
	repe(k, 1, n) {
		X = (X + (2 * k - n - 1)*x[k]) % MOD;
	}
	ll Y = 0;
	repe(k, 1, m) {
		Y = (Y + (2 * k - m - 1)*y[k]) % MOD;
	}

	cout << X * Y % MOD << endl;
	return 0;
}