Consider the following reaction:
\( 3\mathrm{PbCl_2} + 2(\mathrm{NH_4})_3\mathrm{PO_4} \rightarrow \mathrm{Pb_3(PO_4)_2} + 6\mathrm{NH_4Cl} \)
If \( 72 \) mmol of \( \mathrm{PbCl_2} \) is mixed with \( 50 \) mmol of \( (\mathrm{NH_4})_3\mathrm{PO_4} \), then the amount of \( \mathrm{Pb_3(PO_4)_2} \) formed is ______ mmol. (Nearest integer)
