I have 600 TIFF files in a directory, c:\temp.

The file names are like:

```
001_1.tif,
001_2.tif,
001_3.tif

002_1.tif,
002_2.tif,
002_3.tif
....
....
200_1.tif,
200_2.tif,
200_3.tif

```

The combined files should be placed in same directory and the files should be named like:

```
1_merged.tif
2_merged.tif
.....
.....
200_merged.tif

```

I am looking for any single command-line /batch-file to do so through ImageMagick `convert`/ `mogrify` command or any other command/tools.

Please note the overall time taken should not be more than 5 second.