function getNoun(number, one, two, five) {
let n = Math.abs(number);
n %= 100;
if (n >= 5 && n <= 20) {
return five;
}
n %= 10;
if (n === 1) {
return one;
}
if (n >= 2 && n <= 4) {
return two;
}
return five;
}
alert("4 " + getNoun(4, 'слон', 'слона', 'слонов'));