// No.1903 Day1
package main

import "fmt"

func main() {
	var n int
	fmt.Scan(&n)

	d := 1
	for {
		if d%7 == 0 {
			n += 6
		}
		n--
		if n == 0 {
			break
		}
		d++
	}
	fmt.Println(d)
}