const map = { 0: 0, 1: 1 };
function downToZero(n) {
    for (let i = 2; i <= n; i++) {
        if (map[i]) continue;

        let a = 2;
        let min = map[i - 1];
        let b;
        while (a <= (b = i / a)) {
            if (Math.floor(b) === b) {
                min = Math.min(min, map[b]);
            }
            a++;
        }
        map[i] = min + 1;
    }
    return map[n];
}