package main

import (
	"fmt"
)

func main() {
	solve280()
}

func solve280(){
	var N, z, pre_z, a, b int
	a = 1
	b = 1
	fmt.Scan(&N)
	fmt.Scan(&z)
	pre_z = z
	for i:=1; i<N; i++ {
	    fmt.Scan(&z)
		a *= pre_z
		b *= z
		pre_z = z
		x := gcd(a, b)
		if x!=0{
			a = a/x
			b = b/x
		}
		}
	fmt.Printf("%d/%d\n", b, a)
	return
}

func gcd(a, b int)int{
	if a<b{
		a, b = b, a
	}
	if b==0{
		return a
	}else{
		return gcd(b, a%b)
	}
}