Aditi shifted to a new apartment and noticed that her bedroom's wall is too plain. The wall has the dimensions n∗m which is in the form of a grid. She wanted to decorate it with photos and stickers.
She has long streams of photos which she would want to place on the ith row, ranging from column j1 to column j2.
She has k such photo streams. She also knows that there might be some vacant cells on the wall. She decides to buy and stick one sticker on each of the cell. But she doesn't know how many stickers she needs to buy
Help her find how many stickers she has to buy so that there won't be any vacant spot on the wall
INPUT FORMAT
The first line contains three space-separated integers describing the respective values of n, m and k.
Each line of the subsequent lines contains three space-separated integers describing the respective values of i, j1, j2 for each photo stream.
OUTPUT FORMAT
Print a single integer, the number of stickers Aditi has to buy
CONSTRAINTS
XXXX XAAX BBBB XXXC
In the above grid, A represents the first photo stream, B the second stream and C, the third.
The Xs shows the vacant spot. As there are 9 of them, Aditi has to buy 9 stickers.