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();
		}
		
		BigInteger upper = BigInteger.valueOf(zs[0]);
		BigInteger lower = BigInteger.valueOf(zs[1]);
		
		for(int i = 1; i < N - 1; i++){
			final BigInteger inner_upper = BigInteger.valueOf(zs[i]);
			final BigInteger inner_lower = BigInteger.valueOf(zs[i + 1]);
			
			upper = inner_upper.multiply(lower);
			lower = inner_lower.max(upper);
			
			final BigInteger gcd = upper.gcd(lower);
			upper = upper.divide(gcd);
			lower = lower.divide(gcd);
		}
		
		final BigInteger gcd = upper.gcd(lower);
		upper = upper.divide(gcd);
		lower = lower.divide(gcd);
			
		System.out.println(lower.longValue() + "/" + upper.longValue());
		
	}

}