How to read a pixelregion of a .tif image

I am trying to read just a portion of my .tif image since reading the entire one takes hours and hours. My code is:

a = imread('landcover.tif','PixelRegion',{[1:96684],[1,1000]});

The error comes up and I do not know why:

Error using imread (line 438)
PixelRegion values must contain [START, STOP] or [START,
INCR, STOP].

But if I only want to look at [1,2], [1,2], it could work:

a = imread('landcover.tif','PixelRegion',{[1:2],[1,2]});

If anyone can help, I will really appreciate it! Thank you!

[Amal George M]

ROWS and COLS must both be two-element vectors, which specify starting and ending rows (or columns).

Try :

a = imread('landcover.tif','PixelRegion',{[1,96684],[1,1000]});