#include <bits/stdc++.h>
#define FastIO ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
using namespace std;
typedef long long ll;
bool solve(ll law, const vector<vector<ll>> &graph, vector<ll> &dp) {
    ll &ans = dp[law];
    if(ans != -1)
        return ans;
    ans = true;
    for(const auto &x : graph[law])
        ans &= !solve(x, graph, dp);
    return ans;
}
int main() {
    FastIO;
    char c;
    ll i, v, N;
    cin >> N;
    vector<vector<ll>> graph(N);
    for(i = 0; i < N; i++) {
        cin >> c;
        if(c == 'R')
            continue;
        cin >> v;
        graph[v - 1].push_back(i);
    }
    vector<ll> ans;
    vector<ll> dp(N, -1);
    for(i = 0; i < N; i++) {
        if(solve(i, graph, dp))
            ans.push_back(i + 1);
    }
    cout << ans.size() << '\n';
    for(const auto &x : ans)
        cout << x << ' ';
    cout << '\n';
    return 0;
}