package main

import "fmt"

func main() {
	var input string
	fmt.Scan(&input)
	s := input
	fmt.Scan(&input)
	s += input

	ans := 0
	cnt := 0

	for _, c := range s {
		switch c {
		case 'o':
			cnt++
		case 'x':
			cnt = 0
		}
		ans = max(ans, cnt)
	}
	fmt.Println(ans)
}

func max(a, b int) (res int) {
	res = a
	if b > a {
		res = b
	}
	return
}