function solve (arr) {


    let sumLeft = 0;

    let sumRight = 0;



    let lengthOfArr = arr.length;

if (lengthOfArr === 1) {

  return 0;

}




      for (let i = 0; i < lengthOfArr; i++) {

        if (i > 0) {

        sumLeft += arr[i - 1];

        }

        sumRight += arr[i + 1];




        if (sumLeft === sumRight) {

          return i;

        } else if (i === lengthOfArr - 1) {

          return 'no';

        }


        sumRight = 0;


      }




  }