1. Number Checker

function printNumbers(n) {
    var exist = false;
    var result = '';
    for (var i = 1; i <= n; i+=1) {
        if(i % 4 !== 0 && i % 5 !== 0) {
            exist = true;
            result += i + ', ';
        }
    }

    return exist ? result : 'no';
}



console.log(printNumbers(20));
console.log(printNumbers(-5));
console.log(printNumbers(13));