Problem Statement

There is an $N \times M$ grid, where the square at the $i$-th row from the top and $j$-th column from the left has a non-negative integer $A_{i,j}$ written on it. Let us choose a rectangular region $R$. Formally, the region is chosen as follows.

• Choose integers $l_x, r_x, l_y, r_y$ such that $1 \le l_x \le r_x \le N, 1 \le l_y \le r_y \le M$.
• Then, square $(i,j)$ is in $R$ if and only if $l_x \le i \le r_x$ and $l_y \le j \le r_y$.

Find the maximum possible value of $f(R) =$ (the sum of integers written on the squares in $R$) $\times$ (the smallest integer written on a square in $R$).

Constraints

• All input values are integers.
• $1 \le N,M \le 300$
• $1 \le A_{i,j} \le 300$

Input

The input is given from Standard Input in the following format:

N M
A_{1,1} A_{1,2} \dots A_{1,M}
A_{2,1} A_{2,2} \dots A_{2,M}
\vdots
A_{N,1} A_{N,2} \dots A_{N,M}

Output

Print the answer as an integer.