Have a problem of MHC PPS PORT setup for CAN_RX using PIC32MK (pinetree2105)

Hi,I post my first post today.There are two questions about the MHC for PIC32MK1024MCF064. first is setup for CAN RX PORT using PPS input configuration.there is no drop-down menu for INPUT_FUNC_C*RX, but there is OUTPUT_FUNC_C*TX for PPS Output configurat..