Let N be the set of all natural numbers {0 , 1 , 2 , . . . }, and R be the set of all real numbers. wi, hi for i = 1 . . . n are some elements in N, and w0 = 0. Define set B = { | x, y ∈ R and there exists an index i > 0 such that 0 0wj 0wj} Again, define set S = {A| A = WH for some W , H ∈ R+ and there exists x0, y0 in N such that the set T = { | x, y ∈ R and x0 Your mission now. What is Max(S)? Wow, it looks like a terrible problem. Problems that appear to be terrible are sometimes actually easy. But for this one, believe me, it's difficult.输入描述 The input consists of several test cases. For each case, n is given in a single line, and then followed by n lines, each containing wi and hi separated by a single space. The last line of the input is an single integer -1, indicating the end of input. You may assume that 1 1h1 +w2 h2 +...+wn hn 9.输出描述 Simply output Max(S) in a single line for each case.输入例子 3 1 2 3 4 1 2 3 3 4 1 2 3 4 -1 输出例子 12 14