Problem B
Most Difficult
You are an expert on the most difficult field of math — primes! Indeed, you have actually proven the Riemann Hypothesis, but unfortunately, this margin is too narrow to contain the proof.
Being considered a prime expert, $q$ people have come to you for help. The $i$-th person has a favorite number $x_ i$, and they want to find the primmest prime number with respect to $x_ i$ — that is, the smallest prime number $p$ such that both $p$ and $x_ i + p$ are prime!
Unfortunately, there are too many people, and you don’t want to spend your time answering such trivial questions. Instead, you decide to write a program to answer all of their questions!
Input
The first line contains an integer $q$, denoting the number of people ($1 \leq q \leq 100$).
The next $q$ lines each contain an integer $x_ i$, denoting the favorite number of the $i$-th person ($1 \leq x_ i \leq 10^{18}$).
Output
Output $q$ lines, where the $i$-th line contains the primmest prime $p$ with respect to $x_ i$. If there is no such prime $p$ where both $p$ and $x_ i + p$ are primes, output $-1$ instead.
Sample Input 1 | Sample Output 1 |
---|---|
10 1 2 3 4 5 3233 4200 1000000000 969268337140823504 1000000000000000000 |
2 3 2 3 2 -1 11 7 2837 3 |