Verma has got 2 arrays of integer numbers. He wished to find the sum of product of all numbers in first array with all the
numbers in second array.

i.e suppose 1st array A[] contains N numbers and 2nd array B[] contains m numbers.
He wished to calculate for all 1 ≤ i ≤ N and for all 1 ≤ j ≤ M.. sum(Ai*Bi).

As he is busy watching NARUTO. He seeks your help in finding this.

Input Format
1^st line contains 2 space separated integers N and M.
2^nd line contains N space separated integers Ai.
3^rd line contains M space separated integers Bi.
Output Format
1 single line containing only the required answer.

Constraints

1 ≤ N,M ≤ 10^5
-1000 ≤ Ai, Bi ≤ 1000

Problem Setter : Sanchit Bhushan
Problem Tester : Pranjul Dubey

SAMPLE INPUT
2 2
1 2
3 4

SAMPLE OUTPUT
21

Explanation

Here answer is
31 + 32 + 41 + 42

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