import collections,sys,math,functools,operator,itertools,bisect,heapq,decimal,string,time,random
#sys.setrecursionlimit(10**9)
#sys.set_int_max_str_digits(0)
#input = sys.stdin.readline
n = int(input())
#alist = list(map(int,input().split()))
#alist = []
s = input()
#n,m = map(int,input().split())
#for i in range(n):
#    alist.append(list(map(int,input().split())))
ans = []
for i in range(n-1):
    if s[i] == 'x' and s[i+1] == 'o':
        ans.append(i+2)
print(len(ans))
print(*ans)