export function fibonacci(value) {
  let beforeLastNumber = 0;
  let lastNumber = 1;
  let nextNumber;
  
  if (value < 2) return value;

  for (let i = 2; i <= value; i++) {
    nextNumber = lastNumber + beforeLastNumber;
    beforeLastNumber = lastNumber;
    lastNumber = nextNumber;
  }

  return lastNumber;
}