function main(input) {
  const data = input.trim().split("\n");
  const N = Number(data[0]);
  const K = Number(data[1]);
  const ns = data.slice(2).map(Number).sort();
  return ns.slice(-1)[0] - ns[0];
}

// Don't edit this line!
console.log(main(require("fs").readFileSync("/dev/stdin", "utf8")));