# This code is generated by [Atcoder_base64](https://github.com/kyomukyomupurin/AtCoder_base64)
# Original source code : 

"""
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#include <cmath>
#include <complex>
#include <cstring>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

using namespace std;

using int64 = long long;

#define all($) begin($), end($)
#define rall($) rbegin($), rend($)

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  int64 a, b, c, d; cin >> a >> b >> c >> d;
  cout << max({a * c, a * d, b * c, b * d}) << endl;

  return 0;
}

"""

import base64
import subprocess
import zlib


exe_bin = "c$~die{5UD9Y5P~;<Sn5h89B0R<ER5QWO)nX>iwd#7^8kZ%*2#4(k~0^~HATM;$w|pTX(a<|zfu3t<srsA$@Rs5F7JA0Qz#ZAeQS1lz>4^p9;!FsV#{5(Fbt`O&d8-uLd^+3%g-8w^dm$oby)bKmdx?!Nc?`@R{D?zh`)h$jd70;1eHjUQn6!j`HCU;)$&|38IpK#jmR=;TCt#b%_gYCW1>z^?Hky#X1iO-G%`I$dcoQiQx!J<`@xtA?gpy$1R?tGB~x)Uz|a64NU&c}@}2<COQWf&F3(7wHf((gsEky{;xm{-O06FH$SL!=TrQK7R5rI?C#^^2=G)UQYQq+?-a%`}=NACwkIKrcmrD2KsyY`+WJVZzpY&hshoo8Kd%Kyt%7L`9_A3@|8y}w|?-M*tzoUC$>f3yYR#l6TjR^WZkGXZeY=F15G!xvGHunVE*AIZn7>t1;2I^{I?ePC{(n~1Rt}I58KS~J`4OU3p*|g`K^f0Kx2|E<UJPhdoA!sEZXA*`x{UP8t`aZ9yZ|fNW)KT(C`jE5nvwV)kOTJo5<MrBaBZ@W-~ai$~hHdgd?$GoJi)9CzZUK%*BQW)7eZiCXc6+TA6vt?MKwUWG0c0#E+<ce>^4Uu$q$<H6MwG!=r%h8kh4*9B1=tE-6n&VmQ`|!$<ltRoxX=GLRWLq6U;~9)oDIFOpHzA%FNTif8xWVXS2G$($M~5`)<o78Lxu^V69)zFSdK(3ymi4Uba^#or6M$s#l-&XkqWI&E6rpjI7pC7vy)#8GkXBXCdr6pp7(;R#tu0}wCDSXProMP<x{l9AKOY48Omip-&tGW6^~G!h!bJAHlC+)m$aEr0YV-o<e(@7qHL$qs9+f&QE{&-V=n{UgZ+_zs&kk9y&^QBhjSPMc>~VYAXqw7$;9oyglzZ68s)A9N9WWhP(#X1ATx`#mPl_Y=N9BDSAR3HVa8MvDTzz|JF=$B1)&sZFDe2(cb%=_MWBtivzq@O3(TS%<IJ;j22lMTcL};jKEHuOD)pxOF&RKLl^n;b)nhCRE#FNqSU=>o>c{b$Ejge^Q6*&&i+baQ!*4pu?MV_^)-iONUD{Z@Hvd=TDlvNV<1HwO5v;nde-K)$+>jolsQS-Ut8Nwhlm!@F`NXa;XAo`wqgBF0L$5ejDLQ*H#uNznSo42v?q@d^_Pu7grvo{5ryuuC2^d-cESZrIixpKWy}(iFsXnkNPVKX|`c|7h%goosxfHxd4*V+`i*3=tlVs=>=z?S?lle_i2gR>5|GXEI+^)4`IH=m=40IgqdyVlx9ikY!uMhdx+8nsqJTfgx`7ieIS)%onBIB7jVCq_FRzWD4=%sN^>EQj&=s_aY*GQX)ge$JyP4j7o?dB9niFM&<$y?3y=%aZ13{ZYfvB5`yx>P0;y0+NV{5SrwUFOgQJVfOKY@KkC9HnFfCsq{OrCB#M0cR&6MmuLrb4?tvm>&6Z8JJBjt<7rSe~;nb%ei#iDc0J7H|3xz@|XTXXxK1*yuWXPjR2Zrj!&3jG<FF=@_u5va81id24Gy&k5-cbwXkXgyZBG~sL8dWQP**dmz)H6HXIango7NX>MwfxdKp4V<tlonO9HvOO<dTvNfD&cn=L3o&SAue9$e7=Ki_S(@2bX@J}qX-^Audk3g5zkRh*S(cy+&pXQ?XCvw*qIY?5g7$}qA6uCK35^eaIe1&7{HNep5PY$HznylqX9VbxVEJmK{C>3ib-D)5Uv(_M^Dl7ly>F{t|I55R(ej7U^7}*OcY>9TuSheCHfhga3U3mJfAv`Kj^MH2@gQEDueJa3B3n~z714cli(~HqTYJw!754-EJapt~Vjt*>gokli2AT$X2he+<2MsWCZvl<kwEGoFw$r1?R`l4mv^2TqZA~76lRLEw^ls9vYjb&oI+=VIw1Ya%?b+|{_+s1oyIm!8>*l>Xc6Dy!`s7Yp0y+JD(E&fwz9QhO1Q>Fku)nd+?Fz1^WkuE}A1V8i+jHElX%kxy!EXxMnIu5S?fI@f<nDOD5q5j$8ba=_`<;@z_r6BS9hhkvb`Rv-fuOrL=<W)+y&wnjA+SZxqF3N|7VKDF7XKfK9VYyI<L8<FU8AQvScac9z09fnj5)*XUC(%azVc@pKbJQ%%Fk2&p5kNl-dZI~D8JwHGh=`qD*UWiVCDR*JZCd>i;g8pn~*W_v$(|06FvryGs@>3KYOlY^xI8FJk@Ayx0lt=&vah@r;$<apB1ftHU_OR-o@-y7|+|a%J|oqBmTj7{TcheOx1U!kS16M?qc*lMjvMMM~pth==1tT_X!feM;#a({G7LIY`l<B3*K9NyM4Vqy9$)^f5RW}_4ajZ=*O|?0Ivs37M%mU9W%upNHxV9s`Jx`JFD~3h&NW}uMuymj;j%ORp)~dZ?4WeBfhRWKaKeM>N+*zE$EOb-inq?aW}eTinmqQy%G1Ic~g8tHEv+U+tEv=_%+pi#E5UK?jJ^clj;0*plhq^-H5~L_L$+d_oflQz78YHz5)HcBI4H|vWDH&{nf|t&r+QZG~Mp4>XX!OVJFD!^sY1FgAAV%@Y@)^AmC|MZ&9fCYcyZ)&&QY@B#g^XseJvoShfFmRK6X(+ai{j%fC$j*Uyu`Q9JeH`vLubO<nt4HVqfsxy458)XxV$eJ5UrJi@r&X(#cD`gszdaf#YI=ga$mMLZ;Hf&b7V&O@+v-MU+4_%AH%*rA;p?AKNIO`e(@M81BVw%N_?Wb9hK{9xsGvTh6cmnmMq&xBcfM1LN(o5yp=i_2r;X9pdZ4peG4;suNLJZjhE#d?2iA%Bte*TejiWcaIg^ElO2CSPLme7kRTn8%}TbePv0a+upcY=NJ$u!BPQP%fJ&#8o^j7k%-mDTEJ14~BwKjPr$Y9MNJlB<vFnV60@7jH04=PR*-@i3wjE)q-JIoy2hx^vWZQ6IpyRogJ6cIH6{9c`O%-D4w01N+;E1!govmo`AU!2^1+<&gJB3oXn`XX*7|OCzCi)n4Fvj6&;63Qw*XQ?;i~ghjDmhh{WpffsrvBmKZ1vjUqhsm670ZWDv>>$_XPtgHu&M9NfSENH~UL!B8{|R+9-?l@X2{q;a$iF65I5%P8EyfH8LUkwH0wf)G1nWh_AU$%Bew9f^Dvr)02{G(_%%>VzO)t(2IE4G(g!^8jI8E#NlpS?j=Kox|{WKCe?ViAjnT(fDFKU!WuUpCh(4Su*Xa!B$g?wTPwYnED8@MHJXHf@`b{`SR0~syq%<&1p2nb4mtGP9a|=t0sNHP^3qdPcrUgrr;YdDCtCxl0cM8$@vuWC8jfAPorv1E4eF~%PZN8fx%FgOQvNa$Z}I@l~f5XBw63dEM#C_z<=s1AM6@rA^4IhwkT7HT#eIIwe_TF@I2HYPbzW9P<0qy<b$1I5|*&p{`6la@?IocC*N1CzQgfk6ZjjEF*YfF=kf~j;<el_==1wOr=1_6PvQjc!yAq3i{God7|yT#;<b7NX;&_;&)*ZAmRN_$Gr*?P=kHB&|I>fl;_nVl&j}6_{dXK`Z&0q!-zS`Uh4u@d8__AGy=ghm-!Yt?K(+SUQGNeUBh9B=pTBoF<?n3Kf4u)^n0|=y{9VK;f9DhZYfbbYK>BZdwKxZ-JRZQ4IR0fppTDy>EeY}-fj%VY^Y<91qQ6`M{ehs*?~j~5CcIBQMi!kD^!dG!(`G?l?Ee!?pWjvZ{aCywi~5{Cg^cUp>U*<Q{l60Q`MZ)+uQ1_7fBpt(-$!_ysP_F?<3)do{{I8gzN2t`{w^uDn%5`lzlx0CjB4Na8NfQ$DCqHaokd#z#W+`qecUO1ME!3H`qlfm$5@Z3&(kWyxPJAX&lCrQ`8OcwzsKqq13Fy4TfoiYm1c3(0j9so97oQX9#p^nn{{p1r(U-3=Y>LX|J-1qzrX^YYXUCn{~Kc+v<U"

open("./kyomu", 'wb').write(zlib.decompress(base64.b85decode(exe_bin)))
subprocess.run(["chmod +x ./kyomu"], shell=True)
subprocess.run(["./kyomu"], shell=True)

Measured memory_bytes: 10728