package main

import (
	"fmt"
)

func main() {
	var A, B, C, D, E int
	fmt.Scan(&A, &B, &C, &D, &E)

// 	now := time.Now()
// 	defer func() { fmt.Println(time.Since(now)) }()

	f, s := true, true
	ft, st := A, C
	n := 0
	for e := E; e > 0; {
		d := ft
		if st < d {
			d = st
		}
		if e < d {
			d = e
		}

		//fmt.Fprintf(os.Stderr, "%v: ft=%v, st=%v\n", E-e, ft, st)
		if f && s {
			n += d
		}

		ft -= d
		st -= d
		e -= d

		if !f && !s && ft == 0 && st == 0 {
			r := E - e
			n += n * e / r
			e = e % r
		}

		if ft == 0 {
			f = !f
			if f {
				ft = A
			} else {
				ft = B
			}
		}

		if st == 0 {
			s = !s
			if s {
				st = C
			} else {
				st = D
			}
		}
	}

	fmt.Println(n)
}