After Koying flattened the road, he realised that he still falls over often while walking on the NTHU streets. He believe that there is an issue with his road-constructing strategy, so he did some modifications to the program and simulated its process.
His program simulates the following environment:
There is a grid of N × M cells, representing the map of Hsinchu City. Each cell has a bumpy value (崎嶇值).
A higher bumpy value means a more bumpy, and a bumpy value of 0 represents a flat (平整的) area.
Whenever the road roller passes over a cell, the ground becomes flattened, and the cell's bumpy value is set to 0.
After the modifications, Koying's movement rules are as follows:
Your task is to calculate the total sum of flattened ground's bumpy values.
Note that if a cell is passed over multiple times, it's bumpy value should not be accumulated more than once since each area can only be flattened once.
If Koying manages to flatten all the roads in Hsinchu City, you should output "Road Roller Da!!".
As Koying is currently occupied with helping the power plant at National Tsing Hua University generate electricity, and his absence might lead to a power outage, he has requested you to finish this program so that he can focus on power generation.
No recursion is required in this problem! :)
The first line contains two positive integers, N and M, representing the size of the grid.
Following that, there are N lines, each containing M positive integers Ai, j, indicating the bumpy value of the grid cell at row i and column j.
Constraints:
In the first line, please output a positive integer, representing the total sum of flattened ground's bumpy values.
If the road roller manages to pass over every grid cell, please output "Road Roller Da!!" (without quotation marks) on the second line.
Remember to print a ‘\n’ at the end of the output.