function absoluteNumber(targetNum) {
  if(targetNum > 0) {
    return targetNum;
  }
  else {
    return -targetNum;
  }
}

function runner(x, y, l) {
  const xaxis = Math.ceil(absoluteNumber(x) / l);
  const yaxis = Math.ceil(absoluteNumber(y) / l);
  let turn = 0;

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

  const answer = xaxis + yaxis + turn;
  return answer;
}

let lines = [];
let reader = require('readline').createInterface({
  input: process.stdin,
  output: process.stdout
});

reader.on('line', function(line) {
  lines.push(line);
});

reader.on('close', function() {
  const X = lines[0];
  const Y = lines[1];
  const L = lines[2];

  console.log(runner(X, Y, L));
});