No nocturia , No DM or HTN, he had P.H of surgically removed stone bladder 4-5 years ago. His urinalysis showed mild UTI . U/S showed Multiple stones in the UB and enlarged prostate 40cc.. his flowmetry was 20ml/ sec with no residual urine ,cystoscopy showed larger left lobe of the prostate than the mildly enlarged right one?,what should be next step...