let ans = 0
    if (n === 1) return "Bob"
    else ans++      // because n>0
    function isPrime(i) {
// optimal the loop condition
        let limit = Math.round(Math.sqrt(i)) 
        for (let mod = 2; mod <= limit; mod++) {
            if (i % mod === 0) {
                return false;
            }
        }
        return true
    }
// eleminate the even number except 2 to optimal the loop
    for (let i = 3; i <= n; i += 2) {   
        if (isPrime(i))
            ans++
    }
    return ans % 2 === 0 ? "Bob" : "Alice"