function OpCalculator(homes, homesNeeded, warDamage) {
  // warDamage is 0.5, 1 or 1.5 depending on the war's duration (50%, 100%, 150% war damage)
  var opDamage = 0.01 * warDamage;
  var totalHomesDestroyed = 0;
  var totalOps = 0;
  var homesDestroyed = 0;

  while(totalHomesDestroyed < homesNeeded) {
    homesDestroyed= Math.floor(homes * opDamage);
    homes -= homesDestroyed;
    totalHomesDestroyed += homesDestroyed;
    totalOps += 1;
  }
  return totalOps;
}