#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n;
    cin >> n;
    char str[n + 1];
    cin >> str;
    
    int wakingStates[n + 1];
    int j = 0;
    
    for(int i = 0; i < n; i++)
    {
        if(str[i] == 'x' && str[i + 1] == 'o')
            wakingStates[j++] = i + 2;
    }
    
    cout << j << endl;
    
    for(int i = 0; i < j; i++)
        cout << wakingStates[i] << " ";
    
    cout << endl;
    
    return 0;
}