#include <bits/stdc++.h>

#define LOG(FMT...) fprintf(stderr, FMT)

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

template <class T>
istream& operator>>(istream& is, vector<T>& v) {
  for (T& x : v)
    is >> x;
  return is;
}

template <class T>
ostream& operator<<(ostream& os, const vector<T>& v) {
  if (!v.empty()) {
    os << v.front();
    for (int i = 1; i < v.size(); ++i)
      os << ' ' << v[i];
  }
  return os;
}

const int N = 752, L = 10000010;

int n, rt, cnt;
int pos[N];
char s[L];
int ch[L][2];
bitset<N> trans[N];
bool vis[N];
int dfn[N];
int fail[L], prt[L], belongs[L], lst[L];
int f[N];
int sz[N];
bool g[N][N];
int match[N];
bool matched[N];
bool vx[N], vy[N];

void dfs(int u) {
  static int t;
  vis[u] = true;
  for (int v = 1; v <= n; ++v)
    if (trans[u][v]) {
      if (!vis[v])
        dfs(v);
      trans[u] |= trans[v];
    }
  dfn[++t] = u;
}

bool hgy(int u) {
  vis[u] = true;
  for (int v = 1; v <= n; ++v)
    if (g[u][v]) {
      if (!match[v] || (!vis[match[v]] && hgy(match[v]))) {
        match[v] = u;
        return true;
      }
    }
  return false;
}

void dfs2(int u) {
  vy[u] = true;

}

int main() {
#ifdef LBT
  freopen("test.in", "r", stdin);
  int nol_cl = clock();
#endif

  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  cin >> n;
  rt = cnt = 1;
  for (int i = 1; i <= n; ++i) {
    cin >> s;
    int o = rt;
    for (char* p = s; *p; ++p) {
      if (!ch[o][*p - 'a']) {
        ch[o][*p - 'a'] = ++cnt;
        prt[cnt] = o;
      }
      o = ch[o][*p - 'a'];
    }
    pos[i] = o;
    belongs[o] = i;
  }
  queue<int> q;
  for (int i = 0; i < 2; ++i)
    if (ch[rt][i]) {
      fail[ch[rt][i]] = rt;
      q.push(ch[rt][i]);
    }
  while (!q.empty()) {
    int o = q.front();
    q.pop();
    for (int i = 0; i < 2; ++i)
      if (ch[o][i]) {
        int k = fail[o];
        while (k != rt && !ch[k][i]) k = fail[k];
        k = fail[ch[o][i]] = ch[k][i] ? ch[k][i] : rt;
        lst[ch[o][i]] = belongs[k] ? belongs[k] : lst[k];
        q.push(ch[o][i]);
      }
  }
  for (int i = 1; i <= n; ++i)
    for (int o = pos[i]; o; o = prt[o])
      if (lst[o])
        trans[i].set(lst[o]);
      else if (o != pos[i] && belongs[o])
        trans[i].set(belongs[o]);
  for (int i = 1; i <= n; ++i)
    if (!vis[i])
      dfs(i);
  cerr << "good\n";
  int ans = 0;
  for (int i = 1; i <= n; ++i) {
    for (int j = 1; j <= n; ++j)
      g[i][j] = trans[i][j];
    memset(vis, 0, sizeof(vis));
    if (hgy(i)) {
      ++ans;
    }
  }
  for (int i = 1; i <= n; ++i)
    if (match[i]) matched[match[i]] = true;
  for (int i = 1; i <= n; ++i) {
    if (!match[i])
      dfs2(i);
  }
  cout << n - ans << '\n';
  for (int i = 1; i <= n; ++i)
    if (!vx[i] && !vy[i]) cout << i << ' ';

  return 0;
}