解法一：模拟

加法运算：进行归并操作，对于都有的指数项将系数求和，仅有一边有的项保持原样。
乘法运算：遍历两个数组，指数项相加，系数项相乘。由于遍历完无法保证按指数降序排列，因此要存储起来进行排序。
注意系数为0的项无效，不用输出，但是没有至少一个有效项的话要输出“0 0”。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
public class Main {
    public static void main(String[] args) throws IOException {
        // 读入数据
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String[] strs = reader.readLine().split(" +");
        int lenA = Integer.parseInt(strs[0]);
        Item[] A = new Item[lenA];
        for (int i = 1; i <= lenA; ++i) {
            A[i - 1] = new Item(
                    Integer.parseInt(strs[(i << 1) - 1]),
                    Integer.parseInt(strs[(i << 1)])
            );
        }
        strs = reader.readLine().split(" +");
        int lenB = Integer.parseInt(strs[0]);
        Item[] B = new Item[lenB];
        for (int i = 1; i <= lenB; ++i) {
            B[i - 1] = new Item(
                    Integer.parseInt(strs[(i << 1) - 1]),
                    Integer.parseInt(strs[(i << 1)])
            );
        }
        // 乘法
        mul(A, B);
        System.out.println();
        // 加法
        sum(A, B);
    }
    private static void sum(Item[] A, Item[] B) {
        int lenA = A.length;
        int lenB = B.length;
        int cnt = 0;
        boolean flag;
        int coef = 0, index = 0;
        int p1 = 0, p2 = 0;
        // 归并
        while ((p1 < lenA) && (p2 < lenB)) {
            flag = false;
            if (A[p1].index > B[p2].index) {
                flag = true;
                index = A[p1].index;
                coef = A[p1].coef;
                ++p1;
            } else if (A[p1].index < B[p2].index) {
                flag = true;
                index = B[p2].index;
                coef = B[p2].coef;
                ++p2;
            } else {
                coef = A[p1].coef + B[p2].coef;
                if (coef != 0) {
                    flag = true;
                    index = A[p1].index;
                }
                ++p1;
                ++p2;
            }
            // 本项有效
            if (flag) {
                ++cnt;
                if (cnt == 1) {
                    System.out.print(coef + " " + index);
                } else {
                    System.out.print(" " + coef + " " + index);
                }
            }
        }
        if (p1 == lenA) {
            while (p2 < lenB) {
                index = B[p2].index;
                coef = B[p2].coef;
                ++p2;
                ++cnt;
                if (cnt == 1) {
                    System.out.print(coef + " " + index);
                } else {
                    System.out.print(" " + coef + " " + index);
                }
            }
        }
        if (p2 == lenB) {
            while (p1 < lenA) {
                index = A[p1].index;
                coef = A[p1].coef;
                ++p1;
                ++cnt;
                if (cnt == 1) {
                    System.out.print(coef + " " + index);
                } else {
                    System.out.print(" " + coef + " " + index);
                }
            }
        }
        if (cnt == 0) {
            System.out.print("0 0");
        }
    }
    private static void mul(Item[] A, Item[] B) {
        Map<Integer, Integer> map = new HashMap<>();
        int coef, index;
        for (Item i : A) {
            for (Item j : B) {
                index = i.index + j.index;
                coef = i.coef * j.coef;
                map.put(index, coef + map.getOrDefault(index, 0));
            }
        }
        List<int[]> ans = new ArrayList<>(map.size());
        for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
            coef = entry.getValue();
            if (coef != 0) {
                index = entry.getKey();
                ans.add(new int[]{coef, index});
            }
        }
        if (ans.size() == 0) {
            System.out.print("0 0");
        } else {
            ans.sort(new Comparator<int[]>() {
                @Override
                public int compare(int[] o1, int[] o2) {
                    return -Integer.compare(o1[1], o2[1]);
                }
            });
            System.out.print(ans.get(0)[0] + " " + ans.get(0)[1]);
            for (int i = 1; i < ans.size(); ++i) {
                System.out.print(" " + ans.get(i)[0] + " " + ans.get(i)[1]);
            }
        }
    }
}
class Item {
    // 系数
    int coef;
    // 指数
    int index;
    public Item(int coef, int index) {
        this.coef = coef;
        this.index = index;
    }
    @Override
    public String toString() {
        return "Item{" +
                "coef=" + coef +
                ", index=" + index +
                '}';
    }
}