Flexible vs Semi-rigid URS

To compare the efficacy, safety, success rate, operative time, and cost-effectiveness of flexible ureteroscopy versus semirigid ureteroscopy in the management of upper ureteric stones smaller than 2 cm. The investigators' main concern in this study is Upper third ureteric stones to determine which cases can be treated with Semi-Rigid Ureteroscopy, and which one needs flexible ureteroscopy. This depends on several factors: 1. Division of the upper third of the ureter 2. Stone size 3. Stone impaction 4. Surgeon experience 5. Anesthesia 6. Ureteric dilatation above the stone 7. Mini endoscopy