import java.math.BigInteger;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;

public class Main {

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

}