// yukicoder: No.505 カードの数式2
// 2019.5.12 bal4u

#include <stdio.h>

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif

int in()   // 整数の入力（負数対応）
{
	int n = 0, c = gc();
	if (c == '-') {	c = gc();
		do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
		return -n;
	}
	do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

#define INF 0x7ffffffffffffff
long long dp[22][2];
long long mi, ma;

void minmax(long long v) {
	if (v < mi) mi = v;
	if (v > ma) ma = v;
}

void calc(int i, int a)
{
	mi = INF, ma = -INF;
	minmax(dp[i-1][0] + a), minmax(dp[i-1][1] + a);
	minmax(dp[i-1][0] - a), minmax(dp[i-1][1] - a);
	minmax(dp[i-1][0] * a), minmax(dp[i-1][1] * a);
	if (a) minmax(dp[i-1][0] / a), minmax(dp[i-1][1] / a);
	dp[i][0] = ma, dp[i][1] = mi;
}

int main()
{
	int i, a, N;
	
	N = in()-1;
	dp[0][0] = dp[0][1] = in();
	for (i = 1; i <= N; i++) calc(i, in());
	if (dp[N][0] < dp[N][1]) dp[N][0] = dp[N][1];
	printf("%lld\n", dp[N][0]);
	return 0;
}