a.cpp

#include<bits/stdc++.h>

#define f first
#define s second
#define pb push_back

using namespace std;
const int MAXN = 1e6 + 10;
const int INF = 1e9 + 7;
bool was[MAXN];
vector <int> g[MAXN];
int up[MAXN][23];
int tin[MAXN], tout[MAXN], l;
bool upper(int a, int b){
    return (tin[a] <= tin[b] && tout[a] >= tout[b]);
}

int timer = 0;
void dfs(int x, int p = 0){
    was[x] = 1;
    tin[x] = ++timer;
    up[x][0] = p;
    for (int i = 1; i <= l; i++){
        up[x][i] = up[up[x][i - 1]][i - 1];
    }

    for (int i = 0; i < g[x].size(); i++){
        int to = g[x][i];
        if (!was[to]){
            dfs(to, x);
        }
    }
    tout[x] = ++timer;
}

int lca(int a, int b){
    if (upper(a, b))
        return a;
    if (upper(b, a))
        return b;

    for (int i = l; i >= 0; i--){
        if (!upper(up[a][i], b))
            a = up[a][i];
    }

    return up[a][0];
}

void solve(){
    tout[0] = INF;

    int q;
    cin >> q;
    pair <string, pair <int, int> > a[q + 1];
    for (int i = 0; i < q; i++){
        cin >> a[i].f >> a[i].s.f >> a[i].s.s;
        if (a[i].f == "ADD"){
            g[a[i].s.f].push_back(a[i].s.s);
        }
    }
    l = 0;
    while ((1 << l) < MAXN){
        l++;
    }

    dfs(1);
    for (int i = 0; i < q; i++){
        if (a[i].f == "GET"){
            cout << lca(a[i].s.f, a[i].s.s) << '\n';
        }
    }
}

int main() {

    ios::sync_with_stdio(0);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int ttt = 1;
    //cin >> ttt;

    while (ttt--){
        solve();
    }
    return 0;
}