import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int N = scan.nextInt();
		long[]z = new long[N];
		for(int i = 0; i < N; i++) {
			z[i] = scan.nextLong();
		}
		scan.close();
		System.out.println(z[N-1] + "/" + z[0]);
	}
}