getCredit

function getCredit(weight, grade) {
  var result = 0;
   for (var i = 0; i < grade.length; i++){
     if ( grade[i] != 'i' && grade[i] != 'I' &&  grade[i] != 'f' && grade[i] != 'F' ) {
        result = result + parseInt(weight[i]);
      }
    }
  return result;
}