Buggy python submission (verdict: Time Limit Exceeded):
import sys
input = sys.stdin.readline

# coding: utf-8


def signed_area(p1, p2, p3):
    '''符号付き面積を計算 '''

    area = (((p2[0] - p1[0]) * (p3[1] - p1[1])) - ((p3[0] - p1[0]) * (p2[1] - p1[1]))) / 2
    return area


def convex_hull(p_list):
    '''グラハムの凸包走査 '''

    p_sort = []
    for i in p_list:
        p_sort.append(i[0])

    # x座標が最小のものをリストの先頭に配置。
    min_index = p_sort.index(min(p_sort))
    min_p = p_list.pop(min_index)
    p_list.insert(0, min_p)

    # 座標最小の点と他の点との角度順にソート ソートアルゴリズムに選択の余地が有る。
    p_length = len(p_list)
    count = 0
    index = 0
    while True:
        count += 1
        index += 1

        area_sign = signed_area(p_list[0], p_list[index], p_list[index + 1])

        # 符号付き面積が負ならば点を入れ替え
        if area_sign < 0:
            p_list[index], p_list[index + 1] = p_list[index + 1], p_list[index]
            count = 0

        if count == p_length - 1:
            break

        if index == p_length - 2:
            index = 0

    # 凹部の点を削除する。
    index = -1
    count = 0
    while True:
        index += 1
        count += 1

        area_sign = signed_area(p_list[index], p_list[index + 1], p_list[index + 2])
        if area_sign < 0:
            del p_list[index + 1]
            count = 0

        if count == len(p_list):
            break

        if index >= len(p_list) - 3:
            index = -1
    return p_list

N = int(input())
p = []
ans = 0
for _ in range(N):
    x,y = map(int,input().split())
    p.append((x,y))
if N == 2:
    x0,y0 = p[0]
    x1,y1 = p[1]
    print(abs(x0-x1)+abs(y0-y1))
    exit()

p = convex_hull(p)
n = len(p)
for i in range(n):
    xi,yi = p[i]
    for j in range(i+1,n):
        xj,yj = p[j]
        tmp = abs(xi-xj)+abs(yi-yj)
        ans = max(tmp,ans)
print(ans)

Fixed submission:
import sys
input = sys.stdin.readline

# coding: utf-8


def det(p, q):
    return p[0]*q[1] - p[1]*q[0]


def sub(p, q):
    return (p[0]-q[0], p[1]-q[1])


def get_convex_hull(points):
    # どの3点も直線上に並んでいないと仮定する。
    n = len(points)
    points.sort()
    size_convex_hull = 0
    ch = []
    for i in range(n):
        while size_convex_hull > 1:
            v_cur = sub(ch[-1], ch[-2])
            v_new = sub(points[i], ch[-2])
            if det(v_cur, v_new) > 0:
                break
            size_convex_hull -= 1
            ch.pop()
        ch.append(points[i])
        size_convex_hull += 1

    t = size_convex_hull
    for i in range(n-2, -1, -1):
        while size_convex_hull > t:
            v_cur = sub(ch[-1], ch[-2])
            v_new = sub(points[i], ch[-2])
            if det(v_cur, v_new) > 0:
                break
            size_convex_hull -= 1
            ch.pop()
        ch.append(points[i])
        size_convex_hull += 1

    return ch[:-1]

N = int(input())
p = []
ans = 0
for _ in range(N):
    x,y = map(int,input().split())
    p.append((x,y))
if N == 2:
    x0,y0 = p[0]
    x1,y1 = p[1]
    print(abs(x0-x1)+abs(y0-y1))
    exit()

p = get_convex_hull(p)
n = len(p)
for i in range(n):
    xi,yi = p[i]
    for j in range(i+1,n):
        xj,yj = p[j]
        tmp = abs(xi-xj)+abs(yi-yj)
        ans = max(tmp,ans)
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
input = sys.stdin.readline

N = int(input())
p = []
ans = 0
for _ in range(N):
    x,y = map(int,input().split())
    p.append((x,y))

for i in range(N):
    xi,yi = p[i]
    for j in range(i+1,N):
        xj,yj = p[j]
        tmp = abs(xi-xj)+abs(yi-yj)
        ans = max(ans,tmp)
print(ans)

Fixed submission:
import sys
input = sys.stdin.readline

# coding: utf-8


def det(p, q):
    return p[0]*q[1] - p[1]*q[0]


def sub(p, q):
    return (p[0]-q[0], p[1]-q[1])


def get_convex_hull(points):
    # どの3点も直線上に並んでいないと仮定する。
    n = len(points)
    points.sort()
    size_convex_hull = 0
    ch = []
    for i in range(n):
        while size_convex_hull > 1:
            v_cur = sub(ch[-1], ch[-2])
            v_new = sub(points[i], ch[-2])
            if det(v_cur, v_new) > 0:
                break
            size_convex_hull -= 1
            ch.pop()
        ch.append(points[i])
        size_convex_hull += 1

    t = size_convex_hull
    for i in range(n-2, -1, -1):
        while size_convex_hull > t:
            v_cur = sub(ch[-1], ch[-2])
            v_new = sub(points[i], ch[-2])
            if det(v_cur, v_new) > 0:
                break
            size_convex_hull -= 1
            ch.pop()
        ch.append(points[i])
        size_convex_hull += 1

    return ch[:-1]

N = int(input())
p = []
ans = 0
for _ in range(N):
    x,y = map(int,input().split())
    p.append((x,y))
if N == 2:
    x0,y0 = p[0]
    x1,y1 = p[1]
    print(abs(x0-x1)+abs(y0-y1))
    exit()

p = get_convex_hull(p)
n = len(p)
for i in range(n):
    xi,yi = p[i]
    for j in range(i+1,n):
        xj,yj = p[j]
        tmp = abs(xi-xj)+abs(yi-yj)
        ans = max(tmp,ans)
print(ans)