const sumAll = function(st,end) { if (typeof(st)!== 'number' || typeof(end) !== 'number' || st < 0 || end < 0) return 'ERROR'; let sum = 0; for (let i = Math.min(st,end); i <= Math.max(st,end); i++) { sum += i; } return sum; }; // Do not edit below this line module.exports = sumAll;