package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func main() {
	n := nextInt()
	gears := make([]int64, n)
	for i := 0; i < n; i++ {
		gears[i] = nextInt64()
	}
	fmt.Printf("%d/%d\n", gears[n-1], gears[0])
}

func nextLine() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	i, _ := strconv.Atoi(nextLine())
	return i
}

func nextInt64() int64 {
	i, _ := strconv.ParseInt(nextLine(), 10, 64)
	return i
}