function Main(input) {
  let data = input.split("\n");
  // let data = input.split(" ");
  let x = Number(data[0]);
  let y = Number(data[1]);
  let L = Number(data[2]);

  let turn = 0;

  if (x!==0 && y>=0) {
    turn = 1;
  } else if (x===0 && y>=0) {
    turn = 0;
  } else if (y<0) {
    turn = 2;
  }

  let side = Math.ceil(Math.abs(x)/L);
  let vertical = Math.ceil(Math.abs(y)/L);
  console.log(turn + side + vertical);

}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));