#include <bits/stdc++.h>
#define _rep(i, x, y) for(int i = x; i <= y; ++i)
#define _req(i, x, y) for(int i = x; i >= y; --i)
#define _rev(i, u) for(int i = head[u]; i; i = e[i].nxt)
#define pb push_back
#define fi first
#define se second
#define mst(f, i) memset(f, i, sizeof f)
using namespace std;
#ifdef ONLINE_JUDGE
#define debug(...) 0
#else
#define debug(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#endif
typedef long long ll;
typedef pair<int, int> PII;
namespace fastio{
    #ifdef ONLINE_JUDGE
    char ibuf[1 << 20],*p1 = ibuf, *p2 = ibuf;
    #define get() p1 == p2 && (p2 = (p1 = ibuf) + fread(ibuf, 1, 1 << 20, stdin), p1 == p2) ? EOF : *p1++
    #else
    #define get() getchar()
    #endif
    template<typename T> inline void read(T &t){
        T x = 0, f = 1;
        char c = getchar();
        while(!isdigit(c)){
            if(c == '-') f = -f;
            c = getchar();
        }
        while(isdigit(c)) x = x * 10 + c - '0', c = getchar();
        t = x * f;
    }
    template<typename T, typename ... Args> inline void read(T &t, Args&... args){
        read(t);
        read(args...);
    }
    template<typename T> void write(T t){
        if(t < 0) putchar('-'), t = -t;
        if(t >= 10) write(t / 10);
        putchar(t % 10 + '0');
    }
    template<typename T, typename ... Args> void write(T t, Args... args){
        write(t), putchar(' '), write(args...);
    }
    template<typename T> void writeln(T t){
        write(t);
        puts("");
    }
    template<typename T> void writes(T t){
        write(t), putchar(' ');
    }
    #undef get
};
using namespace fastio;
#define multitest() int T; read(T); _rep(tCase, 1, T)
namespace Calculation{
    const ll mod = 998244353;
    ll ksm(ll p, ll h){ll base = p % mod, res = 1; while(h){if(h & 1ll) res = res * base % mod; base = base * base % mod, h >>= 1ll;} return res;}
    void dec(ll &x, ll y){x = ((x - y) % mod + mod) % mod;}
    void add(ll &x, ll y){x = (x + y) % mod;}
    void mul(ll &x, ll y){x = x * y % mod;}
    ll sub(ll x, ll y){return ((x - y) % mod + mod) % mod;}
    ll pls(ll x, ll y){return ((x + y) % mod + mod) % mod;}
    ll mult(ll x, ll y){return x * y % mod;}
}
using namespace Calculation;
const int N = 1e5 + 5;
int n, T;
vector<int> G[N];
int tot, rt, siz[N], maxn[N];
bool flag, vis[N];
void findrt(int u, int fa){
    siz[u] = 1, maxn[u] = 0;
    for(auto &v : G[u]){
        if(v == fa || vis[v]) continue;
        findrt(v, u), siz[u] += siz[v];
        maxn[u] = max(maxn[u], siz[v]);
    }
    maxn[u] = max(maxn[u], tot - siz[u]);
    if(maxn[u] < maxn[rt]) rt = u, flag = maxn[u] == tot / 2;
}
int ask(int x, int y){cout << "? " << x << ' ' << y << endl; int t; cin >> t; return t;}
void del(int u, int fa){
    vis[u] = 1;
    for(auto &v : G[u]) if(v != fa) del(v, u);
}
int main(){
    cin >> T;
    while(T--){
        cin >> n;
        vector<PII> e;
        vector<int> p;
        _rep(i, 1, n){
            p.pb(i);
            int x, y; cin >> x >> y;
            if(x) G[i].pb(x), G[x].pb(i), e.pb({i, x});
            if(y) G[i].pb(y), G[y].pb(i), e.pb({i, y});
        }
        int res = 0;
        auto work = [&]() -> void{
            vector<PII> cur;
            for(auto &i : p) G[i].clear();
            for(auto &[u, v] : e) if(!vis[u] && !vis[v]) G[u].pb(v), G[v].pb(u), cur.pb({u, v});
            swap(e, cur);
            vector<int> np;
            for(auto &i : p) if(!vis[i]) np.pb(i);
            swap(p, np);
        };
        tot = n;
        while(tot > 1){
            tot = p.size(), maxn[rt = 0] = 2e9, flag = 0, findrt(p[0], 0);
            if(tot == 1) break;
            // debug("rt:%d flag:%d tot:%d\n", rt, flag, tot);
            if(flag && tot % 2 == 0){
                int u = rt, v = 0;
                for(auto &i : G[u]) if(siz[i] == tot / 2) v = i;
                for(auto &i : G[u]) if(siz[i] > siz[u] && siz[u] == tot / 2) v = i;
                int t = ask(u, v);
                if(!t) swap(u, v);
                del(u, v); work();
                continue;
            }
            if(G[rt].size() == 1){
                int u = rt, v = G[rt][0];
                int t = ask(u, v);
                p.clear(); if(t) p.pb(v); else p.pb(u);
                break;
            }
            if(G[rt].size() == 2){
                int u = G[rt][0], v = G[rt][1];
                int t = ask(u, v);
                if(t == 1){
                    p.clear(), p.pb(rt);
                    break;
                }
                if(t == 2) swap(u, v);
                del(rt, u); work();
                continue;
            }
            PII nxt[] = {{G[rt][0], 0}, {G[rt][1], 0}, {G[rt][2], 0}};
            _rep(i, 0, 2){
                int v = nxt[i].fi;
                if(siz[v] > siz[rt]) nxt[i].se = tot - siz[rt];
                else nxt[i].se = siz[v];
            }
            sort(nxt, nxt + 3, [](PII x, PII y){return x.se > y.se;});
            int u = nxt[0].fi, v = nxt[1].fi;
            int t = ask(u, v);
            if(t == 0) del(rt, u);
            if(t == 1) del(u, rt), del(v, rt);
            if(t == 2) del(rt, v);
            work();
        }
        res = p[0];
        cout << res << endl;
        _rep(i, 0, n) vis[i] = siz[i] = maxn[i] = 0, G[i].clear();
        tot = rt = n = 0;
    }
    return 0;
}