Century Crisis

Scientists have discovered that in four decades, the world will EXPLODE! It will also take three decades to make a spaceship to travel to a new planet that can hold the entire world population.

You must calculate the number of people there will be in three decades from now.

• The variable population is the world population now.
• Assume that every month, someone gives birth to more people n.

Return the number of people there will be when the spaceship is complete.

Examples

futurePeople(256, 2) ➞ 976

futurePeople(3248, 6) ➞ 5408

futurePeople(5240, 3) ➞ 6320

Notes

Humanity's fate lies in your calculation.