function Main(input) {
    input = input.trim().split("\n");
    const n = parseInt(input[0].trim());
    const s = input[1].trim();

    let cnt = [];
    for (let i = 0; i < n; ++i) {
        if (s[i] == "o" && s[i-1] == "x")
            cnt.push(i+1);
    }
    console.log(cnt.length);
    console.log(cnt.join(" "));
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));