import std; void main() { long N; readf("%d\n", N); auto a = readln.chomp.split.to!(long[]); auto dp = new long[][][](N, 4, 2); foreach (i; 0 .. 4) dp[0][i][] = a.front; a.popFront; foreach (i; 1 .. N) { foreach (j; 0 .. 4) { dp[i][j][0] = long.min; dp[i][j][1] = long.max; } } void f(ref long x, long y) { if (x < y) x = y; } void g(ref long x, long y) { if (x > y) x = y; } foreach (i, x; a) { foreach (j; 0 .. 4) { foreach (k; 0 .. 2) { f(dp[i+1][0][0], dp[i][j][k]+x); f(dp[i+1][1][0], dp[i][j][k]-x); f(dp[i+1][2][0], dp[i][j][k]*x); if (x != 0) f(dp[i+1][3][0], dp[i][j][k]/x); g(dp[i+1][0][1], dp[i][j][k]+x); g(dp[i+1][1][1], dp[i][j][k]-x); g(dp[i+1][2][1], dp[i][j][k]*x); if (x != 0) g(dp[i+1][3][1], dp[i][j][k]/x); } } } auto res = dp[N-1].map!(x => x.maxElement).maxElement; res.writeln; }