fibonacciSum

const fibonacciSum=(n)=>{
    let prev=0;
    let current=1;
    let sum=1;
    let total=1;
    for(let i=1; i<n; i++){
      sum=prev+current
      total+=sum
      prev=current
      current=sum
    //   console.log('Previous: ', prev)
    //   console.log('Current: ', current)
        
    }

    return total
    
}

console.log(fibonacciSum(6))
console.log(fibonacciSum(5))