Problem:
 Score : 200 points    Problem Statement Given are integers a,b,c and d .
If x and y are integers and a \leq x \leq b and c\leq y \leq d hold, what is the maximum possible value of x \times y ?      Constraints  -10^9 \leq a \leq b \leq 10^9  -10^9 \leq c \leq d \leq 10^9  All values in input are integers.         Input Input is given from Standard Input in the following format:  a  b  c  d       Output Print the answer.        Sample Input 1 1 2 1 1      Sample Output 1 2  If x = 1 and y = 1 then x \times y = 1 .
If x = 2 and y = 1 then x \times y = 2 .
Therefore, the answer is 2 .       Sample Input 2 3 5 -4 -2      Sample Output 2 -6  The answer can be negative.       Sample Input 3 -1000000000 0 -1000000000 0      Sample Output 3 1000000000000000000

Solution (Python):
def LI():return list(map(int,input().split()))
def II():return int(input())
def yes():return print("Yes")
def no():return print("No")
INF=float("inf")
from collections import deque, defaultdict, Counter
from heapq import heappop, heappush
from itertools import product, combinations
from functools import reduce, lru_cache
from math import pi, gcd
from decimal import Decimal

class Combination:
    """
    O(n)の前計算を1回行うことで，O(1)でnCr mod mを求められる
    n_max = 10**6のとき前処理は約950ms (PyPyなら約340ms, 10**7で約1800ms)
    使用例：
    comb = Combination(1000000)
    print(comb(5, 3))  
    """
    def __init__(self, n_max, mod=10**9+7):
        self.mod = mod
        self.modinv = self.make_modinv_list(n_max)
        self.fac, self.facinv = self.make_factorial_list(n_max)

    def __call__(self, n, r):
        return self.fac[n] * self.facinv[r] % self.mod * self.facinv[n-r] % self.mod

    def make_factorial_list(self, n):
        
        
        fac = [1]
        facinv = [1]
        for i in range(1, n+1):
            fac.append(fac[i-1] * i % self.mod)
            facinv.append(facinv[i-1] * self.modinv[i] % self.mod)
        return fac, facinv

    def make_modinv_list(self, n):
        
        modinv = [0] * (n+1)
        modinv[1] = 1
        for i in range(2, n+1):
            modinv[i] = self.mod - self.mod//i * modinv[self.mod%i] % self.mod
        return modinv

class Unionfind:
    def __init__(self, N):
        self.p = list(range(N))
        self.rank = [0] * N
        self.size = [1] * N

    def root(self, x):
        if self.p[x] != x:
            self.p[x] = self.root(self.p[x])

        return self.p[x]

    def same(self, x, y):
        return self.root(x) == self.root(y)

    def unite(self, x, y):
        u = self.root(x)
        v = self.root(y)

        if u == v: return

        if self.rank[u] < self.rank[v]:
            self.p[u] = v
            self.size[v] += self.size[u]
            self.size[u] = 0
        else:
            self.p[v] = u
            self.size[u] += self.size[v]
            self.size[v] = 0

            if self.rank[u] == self.rank[v]:
                self.rank[u] += 1

    def count(self, x):
        return self.size[self.root(x)]


a,b,c,d=LI()

print(max(a*c,b*c,a*d,b*d))

Solution (Python):
a,b,c,d = list(map(int,input().split()))

print(max(a*c,a*d,b*c,b*d))

Solution (Python):
a,b,c,d = map(int,input().split())
ans = max(a*c,a*d,b*c,b*d)
print(ans)

Solution (Python):
a, b, c, d = map(int,input().split())

print(max(a*c, b*d, a*d, b*c))

Solution (Python):
a, b, c, d = map(int, input().split())
print(max(a * c, a * d, b * c, b * d))

Solution (Python):


def Yes(f): print('Yes' if f else 'No')
def YES(f): print('YES' if f else 'NO')
def ispow(x): return int(x ** 0.5) ** 2 == x


res = -float('inf')



a, b, c, d = map(int, input().split())

for i in (a, b):
    for j in (c, d):
        res = max(res, i * j)
print(res)

Solution (Python):
(a, b, c, d) = map(int, input().split())
print(max(b * d, a * c, a * d, b * c))

Solution (Python):
a,b,c,d=map(int,input().split())
print(max(a*c,a*d,c*b,b*d))

Solution (Python):
a, b, c,d = map(int,input().split())
print(max(a*c,a*d,b*c,b*d))

Solution (Python):
a,b,c,d=map(int,input().split())
print(max(a*c,a*d,b*c,b*d))

Solution (Python):
A,B,C,D=map(int,input().split())
print(max(A*C,A*D,B*C,B*D))

Solution (Python):
a,b,c,d = map(int,input().split())
ans = max(a*c, a*d, b*c, b*d)
print(ans)

Solution (Python):
a,b,c,d = map(int,input().split())

print(max(a*c,a*d,b*c,b*d))

Solution (Python):
a, b, c, d = map(int, input().split())

ans = max([a*c, a*d, b*c, b*d])
print(ans)

Solution (Python):
import sys

read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
sys.setrecursionlimit(10 ** 9)
INF = 1 << 60
MOD = 1000000007


def main():
    a, b, c, d = map(int, readline().split())

    print(max(a * c, a * d, b * c, b * d))

    return


if __name__ == '__main__':
    main()

Solution (Python):
a,b,c,d = map(int,input().split())
print(max(a*c,a*d,b*c,b*d))

Solution (Python):
import sys, math
from functools import lru_cache
sys.setrecursionlimit(10**9)
MOD = 10**9+7

def input():
    return sys.stdin.readline()[:-1]

def mi():
    return map(int, input().split())

def ii():
    return int(input())

def i2(n):
    tmp = [list(mi()) for i in range(n)]
    return [list(i) for i in zip(*tmp)]

def main():
    a, b, c, d = mi()
    print(max(a*c, a*d, b*c, b*d))


if __name__ == '__main__':
    main()

Solution (Python):
def main():
    a, b, c, d = list(map(int, input().split()))
    return max(a * c, b * d, a * d, b * c)



print(main())

Solution (Python):
a, b, c, d = map(int, input().split())
print(max(a * c, a * d, b * c, b * d))

Solution (Python):

import sys
sys.setrecursionlimit(10**9)
INF=10**18
MOD=10**9+7
input=lambda: sys.stdin.readline().rstrip()
YesNo=lambda b: bool([print('Yes')] if b else print('No'))
YESNO=lambda b: bool([print('YES')] if b else print('NO'))
int1=lambda x:int(x)-1

a,b,c,d=map(int,input().split())
print(max(a*c,a*d,b*c,b*d))

Solution (Python):
a, b, c, d = map(int, input().split())
print(max(a * c, a * d, b * c, b * d))

Solution (Python):
a, b, c, d = map(int, input().split())
print(max(a*c, a*d, b*c, b*d))