+ محدودیت زمان: ۱ ثانیه + محدودیت حافظه: ۲۵۶ مگابایت ---------- The Do-Barareh military area is like an $n×m$ grid, each cell of which has a specific height. The commander of this military area is looking for a rectangular sub-area of this area, with width and height least $2$, whose its four corner cells are higher than the rest of its cells. He plans to install watchtowers in the corners of this sub-area to monitor the entire sub-area and use it for ammunition storage. Your job is to help the commander to find out how many valid sub-areas there are to choose as the ammunition storage. You can assume cell heights are distinct. # ورودی The first line of input contains two space-separated integers $n$ and $m$ ($2 \leq n, m \leq 750$). Each of the next $n$ lines contains $m$ space-separated integers showing the cell heights. It is guaranteed cell heights are distinct numbers between $1$ and $nm$ (inclusive). # خروجی Print the number of valid sub-areas to be used as an ammunition storage. # مثال ## ورودی نمونه ۱ ``` 3 3 9 4 8 2 1 3 7 5 6 ```` ## خروجی نمونه ۱ ``` 7 ````