An aircraft has to fly over a mountain ridge. The highest obstacle, indicated in the navigation chart, has an elevation of 10 290 ft. The QNH, given by a meteorological station at an elevation of 5 100 ft, is 1013 hPa. The average temperature deviation from ISA is -20°C. What is the minimum safe flight level that should be selected to give a terrain separation of at least 2 000 feet?