function main(input) {
  const data = input.split("\n");
  const X = Number(data[0]);
  const Y = Number(data[1]);
  const L = Number(data[2]);
  return Math.ceil(Math.abs(X) / L) + Math.ceil(Math.abs(Y) / L)
    + X === 0 & Y === 0 ? 0
    : X !== 0 & Y === 0 ? 1
    : X === 0 & Y !== 0 ? Y > 0 ? 0 : 2
    : Y > 0 ? 1 : 2;
}

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