def count_sleep_time(result: str):
    res = []
    for i, x in enumerate(result):
        if x == "o" and result[i - 1] == "x":
            res.append(i+1)
    return len(res), " ".join(map(str, res))


N = int(input())
S = input()
line1, line2 = count_sleep_time(S)
print(line1)
print(line2)