#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

char*mmap();

#define rd_skip() while(*rp++>=48)
#define rd(v) long v=0;{long _c;while(_c=*rp++-48,_c>=0)v=v*10+_c;}
#define wt(v) {long _z=v;do*--wp=_z%10+48;while(_z/=10);}
#define rep(v,e) for(long v=0;v<e;++v)
#define rep3(v,s,e) for(long v=s;v<e;++v)

long ma[1<<6];

void f1(){
	char*rp=mmap(0l,1l<<25,1,2,0,0ll);
	rd_skip();
	while(*rp){
		long a[1<<6];
		rep3(i,1,1<<6){
			long j=i&-i;
			long k=i^j;
			long b;
			if(k){
				b=a[j]*a[k];
			}else{
				rd(v);
				b=v;
			}
			a[i]=b;
			ma[i]=ma[i]>=b?ma[i]:b;
		}
	}
}

long f2(){
	long z=0;
	rep(i0,1)
	rep(i1,2)
	rep(i2,3)
	rep(i3,4)
	rep(i4,4)
	rep(i5,4)
	{
		long j[4]={0};
		j[i0]|=1<<0;
		j[i1]|=1<<1;
		j[i2]|=1<<2;
		j[i3]|=1<<3;
		j[i4]|=1<<4;
		j[i5]|=1<<5;
		long v=ma[j[0]]*ma[j[1]]*ma[j[2]]*ma[j[3]];
		z=z>=v?z:v;
	}
	return z;
}

void f3(long z){
	char wbuf[64],*wp=wbuf+sizeof wbuf;
	wt(z);
	write(1,wp,wbuf+sizeof wbuf-wp);
	_exit(0);
}

int main(){
	f1();
	f3(f2());
	return 0;
}