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++){ BigInteger inner_upper = BigInteger.valueOf(zs[i]); 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()); } }