func divisors_sum[n: i64] : i64
    let k: i64 = n
    let sum = 1

    for i in 2..k+1
        let p = 1
        while k % i == 0
            p = p * i
            k = k / i
        sum = sum * (p * i - 1) / (i - 1)
    return sum - n

func main[] : i64
    let sum = 0

    for i in 2..10000
        let d: i64 = divisors_sum(i)
        if i < d & i == divisors_sum(d)
            sum = sum + i + d
    
    io.println_i64(sum)