Insert mean size in *.rsem.sorted.bam.stats file

[AsoBioInfo]

Hello,

I am just little confused about the inner mate difference needed for TopHat. The rsem.sorted.bam.stats file had been generated during RNA-sequencing. It have an insert mean of 173 bp. Paired-end data run on 50-mer.

The value of option '-r' in TopHat will be 173 or only 73? I think, it should be 173 but I just want to be sure before I start further analysis.

Thanks in advance!
Aso