PLE-4205

A 56-year-old G0 had abnormal postmenopausal bleeding, and a biopsy was done, revealing endometrial adenocarcinoma. The patient underwent EHBSO, PFC, BLND, and the final histopath showed that the tumor is confined to the endometrium. All other pelvic structures and lymph nodes are negative. However, peritoneal fluid cytology was positive. What is the stage?