#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

#define fi first
#define se second
#define pp push_back
#define all(x) (x).begin(), (x).end()
#define Ones(n) __builtin_popcount(n)
#define mem(arrr, xx) memset(arrr,xx,sizeof arrr)
//#define int long long
#define debug(x) cout << (#x) << " = " << x << endl

void Gamal() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
}

const int N = 1000 + 5, INF = INT_MAX, MOD = 1e9 + 7, LOG = 20;

vector<pair<int, string>> adj[N];

map<string, vector<pair<string, string>>> mp;
map<string, bool> vis;
map<string, int> id;

void dfs(string &s) {
    vis[s] = true;
    for (auto &x: mp[s]) {
        if (x.fi != "-1")continue;
        cout << 'W' << ' ' << x.se << endl;
        string nxt, m;
        cin >> nxt >> m;
        x.fi = nxt;
        if (!vis.count(nxt)) {
            for (auto c: m) {
                string a, b = "-1";
                a += c;
                if (a == x.se)b = s;
                mp[nxt].emplace_back(b, a);
            }
            dfs(nxt);
        }
        cout << 'W' << ' ' << x.se << endl;
        cin >> nxt >> m;
    }
}

bool match(string &s, int u) {
    id[s] = u;
    if (adj[u].size() != mp[s].size())return false;
    for (int i = 0; i < adj[u].size(); ++i) {
        if (adj[u][i].se != mp[s][i].se)return false;
        string nxt = mp[s][i].fi;
        int v = adj[u][i].fi;
        if (id.count(nxt)) {
            if (id[nxt] != v)return false;
        } else match(nxt, v);
    }
    return true;
}

void solve() {
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        int k;
        cin >> k;
        for (int j = 0; j < k; ++j) {
            string c;
            cin >> c;
            int v;
            cin >> v;
            v--;
            for (auto &a: adj[i]) {
                if (a.fi == v) {
                    a.se += c;
                    v = -1;
                    break;
                }
            }
            if (~v)adj[i].emplace_back(v, c);
        }
        for (auto &a: adj[i]) {
            sort(all(a.se));
        }
        sort(all(adj[i]), [](pair<int, string> &a, pair<int, string> &b) {
            return a.se < b.se;
        });
    }
    string s;
    cin >> s;
    string nxt;
    cin >> nxt;
    for (auto c: nxt) {
        string a;
        a += c;
        mp[s].emplace_back("-1", a);
    }
    dfs(s);
    for (auto &x: mp) {
        vector<pair<string, string>> v;
        for (auto y: x.se) {
            for (auto &z: v) {
                if (z.fi == y.fi) {
                    z.se += y.se;
                    y.fi = "-1";
                    break;
                }
            }
            if (y.fi != "-1")v.emplace_back(y.fi, y.se);
        }
        for (auto &y: v)sort(all(y.se));
        sort(all(v), [](pair<string, string> &a, pair<string, string> &b) {
            return a.se < b.se;
        });
        mp[x.fi] = v;
    }
    int cnt = 0, node = -1;
    for (int i = 0; i < n; ++i) {
        id.clear();
        if (match(s, i) && id.size() == n) {
            cnt++;
            node = i;
        }
        if (cnt > 1) {
            cout << "R ambiguous" << endl;
            return;
        }
    }
    if (cnt == 1) {
        cout << "R " << node + 1 << endl;
    } else cout << "R no";
}


signed main() {
    Gamal();
    int t = 1;
//    cin >> t;
    while (t--) {
        solve();
    }
}