function harvest(input) {
  let areaWineYard = +input.shift();
  let grapesPerM = +input.shift();
  let wineLitres = +input.shift();
  let count = +input.shift();

  let grapesNeeded = areaWineYard * grapesPerM;
  let wineNeeded = (0.4 * grapesNeeded) / 2.5;

  let diff = Math.trunc(wineNeeded - wineLitres);
  if (wineNeeded >= wineLitres) {
    if (diff) {
      diff / count;
    }
    console.log(`Good harvest this year! Total wine: ${wineNeeded} liters.`);
    console.log(`${diff} liters left -> ${diff / count} liters per person.`);
  } else {
    console.log(
      `It will be a tough winter! More ${Math.abs(diff).toFixed(
        0
      )} liters wine needed.`
    );
  }
}
harvest(["650", "2", "175", "3"]);
harvest(["1020", "1.5", "425", "4"]);