Description

The divisors of a natural number refer to all natural numbers that can divide this natural number without a remainder. For example, the divisors of 6 are: 1, 2, 3, 6. Now, given a number n, find the smallest positive number whose sum of divisors equals n (if no such number exists, output -1).

Input Format

A number n (1 <= n <= 1000000)

Output Format

A number a

```input1 6 ``` ```output1 5 ``` ## 译文

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