Two University of Colorado students climbing the First Flatiron without gear were rescued Friday evening, the Boulder County Sheriff’s Office reported. Emergency officials received a report of two students — wearing tennis shoes, shorts and T-shirts — who had become stranded on the First Flatiron. They were not injured, but they had become stuck just to the north of the Direct East Face route about two-thirds of the way up. A climber in the area of the First Flatironette heard them calling for help and called 911, the sheriff’s office said. Boulder Open Space and Mountain Parks, the sheriff’s office and the Rocky Mountain Rescue Group responded. Members of the rescue group rappelled down to the students and helped them climb to the top of the rock. The rescue took less than three hours, the sheriff’s office said.