package no281;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int z1 = sc.nextInt();
		for(int i=2;i<=n-1;i++) {
			sc.nextInt();
		}
		int zn = sc.nextInt();
		System.out.println(zn + "/" + z1);
	}

}