Input (grade 13): During the 1924 British Mount Everest Expedition, Mallory and his climbing partner Andrew "Sandy" Irvine both disappeared somewhere high on the North-East ridge during their attempt to make the first ascent of the world's highest mountain.
Output (grade 10): Mallory and his climbing partner Andrew Irvine both disappeared somewhere high on the North - East Ridge in an attempt to get to the top.