/* -*- coding: utf-8 -*-
 *
 * 2773.cc:  No.2773 Wake up Record 1 - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 100000;

/* typedef */

/* global variables */

char s[MAX_N + 4];
int cs[MAX_N];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d%s", &n, s);

  int m = 0;
  for (int i = 1; i < n; i++)
    if (s[i - 1] == 'x' && s[i] == 'o') cs[m++] = i;

  printf("%d\n", m);
  for (int i = 0; i < m; i++) printf("%d ", cs[i] + 1);
  putchar('\n');
  
  return 0;
}