monhime

import sys
def input(): return sys.stdin.readline().rstrip()
def main():
    a, b, c, d = map(int,input().split())
    print(max(a*c,a*d,b*c,b*d))

if __name__=='__main__':
    main()

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
def main():
    x = int(input())
    if x == 0:
        print(1)
    else:
        print(0)

if __name__=='__main__':

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
from collections import deque
def main():
    n,m=map(int,input().split())
    graph=[[] for _ in range(n)]
    for i in range(m):
        a,b=map(int,input().split())
        graph[a-1].append(b-1)
        graph[b-1].append(a-1)

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
import math
def main():
    a,b,h,m=map(int,input().split())
    theta_a=(60*h+m)*2*math.pi/720
    theta_b=m*2*math.pi/60
    print(math.sqrt((a*math.cos(theta_a)-b*math.cos(theta_b))**2+(a*math.sin(theta_a)-b*math.sin(theta_b))**2))

if __name__=='__main__':

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
def main():
    k=int(input())
    s=input()
    if len(s)<=k:print(s)
    else:
        print(s[:k]+"...")

if __name__=='__main__':

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
def main():
    n=int(input())
    if n%10==2 or n%10==4 or n%10==5 or n%10==7 or n%10==9:
        print("hon")
    elif n%10==0 or n%10==1 or n%10==6 or n%10==8:
        print("pon")
    else:
        print("bon")

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
class mod_comb3:
    def __init__(self,mod=10**9+7,n_max=1):
        self.mod,self.n_max=mod,n_max
        self.fact,self.inv,self.factinv=[1,1],[0,1],[1,1]
        if 1<n_max:setup_table(n_max)
    def comb(self,n,r):
        if r<0 or n<r:return 0
        if self.n_max<n:self.setup_table(n)

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
def main():
    n,k=map(int,input().split())
    A=list(map(int,input().split()))
    if A[0]==1:
        print(1)
        sys.exit()
    cur_a=1
    cunt=0

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
from itertools import product
def main():
    n,m,x=map(int,input().split())
    CA=[[int(_) for _ in input().split()] for i in range(n)]
    ans=10**10
    n_lis=list(product([True,False],repeat=n))
    for comb in n_lis:
        cunt=0

monhime

import sys
def input(): return sys.stdin.readline().rstrip()
def main():
    a,b,_,k=map(int,input().split())
    if k<=a:
        print(k)
    elif k>a and k<=a+b:
        print(a)
    else:
        print(a-(k-a-b))