diff --git a/th.sh b/th.sh
index 6b3e62f..1044e15 100644
--- a/th.sh
+++ b/th.sh
@@ -6,26 +6,23 @@
 # 2. ImageMagick with modified policy.xml (avaliable on this git)
 #
 # Usage:
-# ./th.sh NFRAMES TILE SIZE INPUT
+# . th.sh COLUMNS ROWS SIZE INPUT
 #
-# NFRAMES is the number of frames (thumbnails) to generate, e.g., 16;
-# TILE is in the form "MxN" (where M * N should match NFRAMES), e.g., 4x4;
+# COLUMNS means number of columns;
+# ROWS means nubler of rows;
 # SIZE is the length of the longer side of the output, e.g., 1920 if you want
 # to get an 1920*1080 output image;
 # INPUT is the path to the input file;
-# OUTPUT is the path to the output file (make sure intermediate directories
-# exist).
 #
 # Example:
-# . th.sh 16 4x4 1920 video.mp4
+# . th.sh 3 14 1920 video.mp4
 if [[ $# != 4 ]]; then
     echo "wrong number of arguments
 
 Usage:
-. th.sh NFRAMES TILE SIZE INPUT
-
-NFRAMES is the number of frames (thumbnails) to generate, e.g., 16;
-TILE is in the form 'MxN' (where M * N should match NFRAMES), e.g., 4x4;
+. th.sh COLUMNS ROWS SIZE INPUT
+COLUMNS means number of columns;TILE is in the form 'MxN' (where M * N should match NFRAMES), e.g., 4x4;
+ROWS means nubler of rows;
 SIZE is the length of the longer side of the output, e.g., 1920 if you want
 to get an 1920*1080 output image;
 INPUT is the path to the input file;
@@ -33,32 +30,23 @@ OUTPUT is the path to the output file (make sure intermediate directories
 exist).
 
 Example:
-. th.sh 16 4x4 1920 video.mp4
+. th.sh 3 14 1920 video.mp4
 "
     return 1
 fi
-
-NFRAMES=$1
-TILE=$2
+NFRAMES=$(echo "scale=0;$1*$2" | bc)
+TILE=$(echo "$1x$2")
 SIZE=$3
 INPUT=$4
-#duration in h:m:s for caption
 DURX=$(ffmpeg -i "$4" 2>&1 | grep Duration | awk '{print $2}' | tr -d ,)
-#duraion in seconds for thumnail generatin
 DURATION=$(ffmpeg -i "$4" 2>&1 | grep "Duration"| cut -d ' ' -f 4 | sed s/,// | sed 's@\..*@@g' | awk '{ split($1, A, ":"); split(A[3], B, "."); print 3600*A[1] + 60*A[2] + B[1] }')
-#resolution of video for caption
 RES=$(ffmpeg -i "$4" 2>&1 | grep -oP 'Stream .*, \K[0-9]+x[0-9]+')
-#filesize in Mb for catopn
 FILESIZE=$(du -sm "$4" | awk '{print $1}')
-# generate thumbnails in the /tmp folder
 TMPDIR=/tmp/thumbnails-${RANDOM}/
 mkdir $TMPDIR
-
 for (( VARIABLE=0; VARIABLE<NFRAMES; VARIABLE++ ))
 do
-#time at which next snapshot is taken and avoiding blank last snapshot: seconds.xx
 OFFSET=$(echo "scale=2;$VARIABLE*$DURATION/$NFRAMES+$DURATION/$NFRAMES/2" | bc)
-#how many zeros we add to temp file thumbnail: bla0009.jpp bla0099.jpg bla0999.jpg
 if [ $VARIABLE -gt 9 ];then
   ZEROS="00"
   if [ $VARIABLE -gt 99 ];then
@@ -72,19 +60,13 @@ else
 fi
 ffmpeg -start_at_zero -copyts -ss $OFFSET -i "$4" -vf "drawtext=fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf:fontsize=45:fontcolor=white::shadowcolor=black:shadowx=2:shadowy=2:box=1:boxcolor=black@0:x=(W-tw)/40:y=H-th-10:text='%{pts\:gmtime\:0\:%H\\\\\\:%M\\\\\:%S}'" -vframes 1 ${TMPDIR}$ZEROS$VARIABLE.jpg
 done
-#combine thumbnails together
 montage ${TMPDIR}*.jpg -background white -geometry +5+5 -tile $TILE ${TMPDIR}output.jpg
-#put info about video in textfile
 echo $4 >>${TMPDIR}myfile.txt
 echo $RES >>${TMPDIR}myfile.txt
 echo "$FILESIZE Mb" >>${TMPDIR}myfile.txt
 echo $DURX >>${TMPDIR}myfile.txt
-#convert textfile in jpg, NB modified policy.xml is needed
 convert -size ${SIZE}x150 -fill black -interline-spacing 10 -background white -pointsize 20 -gravity west caption:@${TMPDIR}myfile.txt ${TMPDIR}text1.jpg
-#resize combined thumbnails
 convert ${TMPDIR}output.jpg -resize ${SIZE}x${SIZE} ${TMPDIR}th.jpg
-#resize info's width to match combined thumbnails
 thewidth=$(identify -ping -format %w ${TMPDIR}th.jpg)
 convert ${TMPDIR}text1.jpg -crop ${thewidth}x150+0+0 ${TMPDIR}text.jpg
-#combine info and thumbnails into output file
 montage ${TMPDIR}text.jpg ${TMPDIR}th.jpg -background white -geometry +0+0 -tile 1x2 thumbnails-${RANDOM}.jpg