Chess board (2) P13623

Consider a chess board with $r$ rows and $c$ columns, where every square contains between 0 and 9 coins. Supose that the upper-left square is white. For instance, this is an empty board with four rows and five columns:

Write a program such that, given a chess board, computes the total number of coins on its white squares.

Input

Input begins with the number of rows $r$ and the number of columns $c$. Follow $r$ lines, each one with $c$ characters between ‘0’ and ‘9’.

Output

Print the total number of coins on the white squares of the board.