package main

import "fmt"

func main() {
	var n int
	var s string
	fmt.Scan(&n,&s)
	x := 0
	y := ""
	for i:=1; i<n; i++ {
		if s[i-1]=='x'&&s[i]=='o' {
			k:=i+1
			if x>0 {
				y += " "
			}
			x++
			y += fmt.Sprint(k)
		}
	}
	fmt.Println(x)
	fmt.Println(y)
}