#include <bits/stdc++.h>
using namespace std;
#define int long long
constexpr int N = 20 + 7;
constexpr int inf = 1E18, mod = 1e9 + 7;
int l[N], r[N], n, max_id, maxk;
bool has_father[N];
inline void dfs(int u, int k) {
    if(u == -1) return ;
    if(k > maxk) {
        maxk = k;
        max_id = u;
    }
    dfs(l[u], 2 * k);
    dfs(r[u], 2 * k + 1);
}
inline void Solve() {
    memset(l, -1, sizeof l);
    memset(r, -1, sizeof r);
    cin >> n;
    for (int i = 0; i < n; i ++) {
        string a, b; cin >> a >> b;
        if(a != "-") {
            l[i] = stoi(a);
            has_father[stoi(a)] = true;
        }
        if(b != "-") {
            r[i] = stoi(b);
            has_father[stoi(b)] = true;
        }
    }
    int root = 0;
    while(has_father[root]) root ++;
    dfs(root, 1);
    if(maxk > n) {
        cout << "NO" << " " << root << '\n';
    }else {
        cout << "YES" << " " << max_id << '\n'; 
    }
}
signed main() {
    cin.tie(nullptr) -> sync_with_stdio(false);
    int T = 1;
    for (; T; T --) Solve();
    return 0;
}