Input (grade 13): It is the fourth-deadliest school massacre in United States history, after the 1927 Bath School disaster, 2007 Virginia Tech massacre and the 1966 University of Texas massacre, and the deadliest for an American high school.
Output (grade 10): It was one of the first well-known massacres at a school in the United States, and the one with the most deaths until the Virginia Tech massacre in 2007.