import mooc.*;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.ArrayDeque;
import java.lang.Math;

class RadixSort {
    static int digit(int x, int k) {
        for (int i = 1; i <= k - 1; i++) {
            x /= 10;
        }
        return x % 10;
    }

    static ArrayList<Integer> sort(ArrayList<Integer> lst) {
        int c[] = new int[10];

        for (int i = 0; i <= 9; i++) {
            ArrayList<Integer> b = new ArrayList<Integer>();

            for (int j = 0; j <= 9; j++) {
                c[j] = 0;
            }

            for (int j = 0; j < lst.size(); j++) {
                int num = lst.get(j);
                int d = digit(num, i);
                c[d] += 1;
                b.add(0);
            }

            for (int j = 1; j <= 9; j++) {
                c[j] += c[j - 1];
            }

            for (int j = lst.size() - 1; j >= 0; j--) {
                int d = digit(lst.get(j), i);
                b.set(c[d] - 1, lst.get(j));
                c[d] -= 1;
            }

            lst = b;
        }

        return lst;
    }
}

class Index {
    public static void main(String args[]) {
        try (EdxIO io = EdxIO.create()) {
            int n, m;
            int a[] = new int[6010];
            int b[] = new int[6010];
            long ans = 0;
            ArrayList<Integer> lst = new ArrayList<Integer>();

            n = io.nextInt();
            m = io.nextInt();

            for (int i = 0; i < n; i++) {
                a[i] = io.nextInt();
            }
            for (int i = 0; i < m; i++) {
                b[i] = io.nextInt();
            }

            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    lst.add(a[i] * b[j]);
                }
            }

            lst = RadixSort.sort(lst);

            for (int i = 0; i < n * m; i += 10) {
                ans += lst.get(i);
            }

            io.print(ans);
        }
    }
}