// No.1902 AC Ratio
package main

import (
	"fmt"
	"strconv"
	"strings"
)

func main() {
	var s string
	fmt.Scan(&s)

	correct, total, _ := strings.Cut(s, "/")
	c, _ := strconv.ParseFloat(correct, 64)
	t, _ := strconv.ParseFloat(total, 64)
	fmt.Printf("%.5f", c/t)
}