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# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;

class Program
{
	static void Main(string[] args)
	{
		int xCount, yCount;
		string[] vals = Console.ReadLine().Split(' ');
		xCount = int.Parse(vals[0]);
		yCount = int.Parse(vals[1]);

		string[] strXSeq = Console.ReadLine().Split(' ');
		string[] strYSeq = Console.ReadLine().Split(' ');
		
		int[] xSeq = new int[strXSeq.Length];
		for(int i = 0 ; i < xSeq.Length ; i++){
			xSeq[i] = int.Parse(strXSeq[i]);
		}
		int[] ySeq = new int[strYSeq.Length];
		for(int i = 0 ; i < ySeq.Length ; i++){
			ySeq[i] = int.Parse(strYSeq[i]);
		}
		
		int sumSquare = 0;
		
		//all
		sumSquare += (Math.Abs(xSeq[xSeq.Length - 1] - xSeq[0]))*(Math.Abs(ySeq[ySeq.Length - 1] - ySeq[0]));
		
		//XY
		for(int xIdx = 1; xIdx < xSeq.Length ; xIdx++){
			for(int yIdx = 1; yIdx < ySeq.Length ; yIdx++){
				sumSquare += Math.Abs(xSeq[xIdx] - xSeq[xIdx - 1])*Math.Abs(ySeq[yIdx] - ySeq[yIdx - 1]);
			}
		}
		
		//X
		for(int yIdx = 1; yIdx < ySeq.Length ; yIdx++){
			sumSquare += Math.Abs(xSeq[xSeq.Length - 1] - xSeq[0])*Math.Abs(ySeq[yIdx] - ySeq[yIdx - 1]);
		}	
		//Y
		for(int xIdx = 1; xIdx < xSeq.Length ; xIdx++){
			sumSquare += Math.Abs(ySeq[ySeq.Length - 1] - ySeq[0])*Math.Abs(xSeq[xIdx] - xSeq[xIdx - 1]);
		}
		
		int ans = sumSquare % 1000000007;
		Console.WriteLine(ans.ToString());
	}
}