import java.util.Scanner;


public class Main_yukicoder280 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();

        int[] z = new int[n];
        for (int i = 0; i < n; i++) {
        	z[i] = sc.nextInt();
        }

        System.out.printf("%d/%d\n", z[n - 1], z[0]);

        sc.close();
    }
}