https://www.acmicpc.net/problem/1037

약수.java

import java.util.*;

public class Main {
	public static void main(String args[]) {
      Scanner sc = new Scanner(System.in);
      int N = sc.nextInt();
      int[] realDivisor = new int[N];
      for(int i=0; i<N; i++)
         realDivisor[i] = sc.nextInt();
      sc.close(); Arrays.sort(realDivisor);
      System.out.print(realDivisor[0]*realDivisor[N-1]);
   }
}