let n = 1
let sleep = "x".map{String($0)}
var ansArray:[Int] = []
for i in 1..<n{
    if sleep[i] == "o" && sleep[i-1] == "x"{
        ansArray.append(i+1)
    }
}
let ans = ansArray.map{String($0)}.joined(separator: " ")
print(ansArray.count)
print(ans)