function main(input) {
  let [b] = getIntegers(input);
  let [n] = getIntegers(input);
  let c = input.map(x => Number(x));
  
  let low = 0;
  let high = Math.floor(c.reduce((a, b) => a + b, b) / n);
  while (high - low > 2) {
    let c1 = Math.floor((low * 2 + high) / 3);
    let c2 = Math.floor((low + high * 2) / 3);
    if (solve(c1, c) > solve(c2, c)) {
      low = c1;
    } else {
      high = c2;
    }
  }
  let min = Number.MAX_SAFE_INTEGER;
  for(let i=low; i<=high; i++) {
    min = Math.min(min, solve(i, c));
  }
  console.log(min);
}

function solve(v, c) {
  let num = 0;
  for(let i=0; i<c.length; i++) {
    num += (Math.abs(v - c[i]));
  }
  return num;
}

//-- functions ------------------------------------

function getIntegers(lines) {
  return lines.shift().split(" ").map(function(e) {
    return Number(e);
  });
}

function getStrings(lines) {
  return lines.shift().split(" ");
}

function twoDimensionalArray(h, w, value) {
  const list = new Array(h);
  for(let i=0; i<h; i++) {
    list[i] = new Array(w).fill().map(function(e) {
      return value.constructor == Array ? Array.from(value) : value;
    });
  }
  return list;
}

//-- Array -------------------------------------------

Array.prototype.pushNoSameValue = function(...values) {
  values.forEach(function(e) {
    if(!this.includes(e)) {
      this.push(e);
    }
  }, this);
};

Array.prototype.sortByIntegers = function() {
  this.sort(function(a, b) {
    return a - b;
  });
};

Array.prototype.oneLineString = function() {
  let str = "";
  this.forEach(function(e, i) {
    if(i > 0) str += " ";
    str += e;
  });
  return str;
};

main(require("fs").readFileSync("/dev/stdin", "utf8").trim().split("\n"));