MM rqrmnt

Hi frnz, in one of my MM requirement, user should be given to enter a prefix, the system should check the entries starting with that prefix in table MARA and should display next possible material no. to create. For example, user enters MAT as prefix, the system should search MARA for matnr starting with MAT n should give next possible matnr starting with MAT. Any suggestions on this requirement? please give some piece of coding also. Thanks in advance.