#include <bits/stdc++.h>
#ifndef ONLINE_JUDGE
#include "lib.h"
#endif
#define rep(i, min, max) for(int i = (min); i <= (max); ++i)
#define nrep(i, max, min) for(int i = (max); i >= (min); --i)
#define reads(str) (scanf("%s", str + 1), strlen(str + 1))
#define case() int Ts = read(); rep(T, 1, Ts)
#define putf(flag) puts((flag) ? "Yes" : "No")
#define put(x) printf("%d ", x)
#define putl(x) printf("%lld ", x)
#define endl() putchar('\n')
using namespace std;

typedef long long ll;
inline int read()
{
    int now=0; bool nev=false; char c=getchar();
    while(c<'0' || c>'9') { if(c=='-') nev=true; c=getchar(); }
    while(c>='0' && c<='9') { now=(now<<1)+(now<<3)+(c&15); c=getchar(); }
    return nev?-now:now;
}

const int N = 1e6 + 10;

int n;
int ls[N], rs[N], vis[N], fa[N];
int siz[N];
int deg[N];

int ask(int x, int y) {
    printf("? %d %d\n", x, y); fflush(stdout);
    return read();
}

int p = 0, mn = 1e9;
void dfs(int x) {
    if(vis[x] || !x) { siz[x] = 0; return; }
    int l = ls[x], r = rs[x];
    dfs(l), dfs(r);
    siz[x] = 1 + siz[l] + siz[r];
    int cur = max({siz[l], siz[r], n - siz[x] + 1});
    if(cur <= mn) p = x, mn = cur;
}

int main() {
    case() {
        n = read();
        rep(i, 1, n) ls[i] = read(), rs[i] = read();
        rep(i, 0, n) deg[i] = 0, vis[i] = 0;
        rep(i, 1, n) deg[ls[i]] ++, deg[rs[i]] ++, fa[ls[i]] = i, fa[rs[i]] = i;
        int rt = 0;
        rep(i, 1, n) if(deg[i] == 0) rt = i;
        int last = 1e9;
        // ok();
        while(1) {
            p = 0, mn = 1e9;
            dfs(rt);
            // print(rt, siz[rt]);
            fflush(stdout);
            // assert(siz[rt] <= last / 2);
            if(siz[rt] == 1) {
                printf("! %d\n", rt); fflush(stdout);
                break;
            }
            int l = ls[p], r = rs[p];
            // print(rt, p, l, r, mn);
            if(l != 0 && r != 0) {
                int op = ask(l, r);
                if(op == 0) rt = l;
                if(op == 2) rt = r;
                if(op == 1) vis[l] = vis[r] = 1;
            } else {
                // assert(l || r);
                int son = l | r, fa = ::fa[p];
                if(mn <= siz[rt] / 2) {
                    int op = ask(p, son);
                    if(op == 0) vis[son] = 1;
                    if(op == 2) rt = son;
                } else {
                    assert(siz[p] == siz[rt] / 2 + 1);
                    int op = ask(fa, son);
                    if(op == 0) vis[p] = 1;
                    if(op == 2) rt = son;
                    if(op == 1) vis[son] = 1, rt = p;
                }
            }
            last = siz[rt];
        }
    }
}