E. Prime Segment
*special; brute force; math; number theory
Positive integer number x is called prime, if it has exactly two positive integer divisors. For example, 2, 3, 17, 97 are primes, but 1, 10, 120 are not.You are given an integer number n, find the shortest segment [a, b], which contains n (i.e. a ≤ n ≤ b) and a, b are primes.
The only given line contains an integer number n (2 ≤ n ≤ 10000).
Print the space separated pair of the required numbers a, b.