fun main() {
    val n = readln().toInt()
    val s = "." + readln()

    val ans = mutableListOf<Int>()
    for(i in 2 .. n) {
        if(s[i-1] == 'x' && s[i] == 'o') {
            ans.add(i)
        }
    }

    println(ans.size)
    println(ans.joinToString(" "))
}