accessing timestep


I am computing the fluid center of mass in an entity and printing them out in a file with the following scripts. my question is that how can I print the timestep in the file along the center of mass coordinate? I tried to access it the same way I grab the Center of mass, but I could not find anything relevant to timestep in ‘compute’ section. do you have any suggestions?
thanks in advance,

compute 1 fluid com

variable x equal c_1[1]

fix 1 fluid print 100 “$x” file COM.txt screen no


Try with the following: